Simplify sweeping of big values #54936

d-netto · 2024-06-26T02:57:28Z

Simplifies the layout of the doubly linked list of big objects to make it a bit more canonical: let's just store a pointer to the previous element, instead of storing a "pointer to the next element of the previous element". This should make the implementation a bit easier to understand without incurring any memory overhead.

I ran the serial and multithreaded benchmarks from GCBenchmarks and this seems fairly close to performance neutral on my machine. We also ran our internal benchmarks on it at RAI and it looks fine from a correctness and performance point of view.

d-netto · 2024-06-26T03:10:16Z

Marking as draft until the x64 failure is investigated.

gbaraldi · 2024-06-26T12:13:59Z

Btw, since you are changing this code, is the linked list an efficient enough data structure for this? I haven't measured the overhead of sweeping through this so I'm not sure but it's potentially a place where we spent some time pointer chasing.

d-netto · 2024-06-27T20:10:33Z

is the linked list an efficient enough data structure for this

Probably?

Note that the sweeping code will need to access the GC bits in bigval_t and the next/prev pointers are in the same cache line as the GC bits, so manipulating the linked list will probably not incur that much extra cost in terms of cache misses.

d-netto · 2024-07-10T19:04:28Z

Latest commit looks fine from a GC time perspective:

master:

category = "TimeZones"
bench = "TimeZones.jl"
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
┌─────────┬────────────┬─────────┬───────────┬────────────┬──────────────┬───────────────────┬──────────┬────────────┐
│         │ total time │ gc time │ mark time │ sweep time │ max GC pause │ time to safepoint │ max heap │ percent gc │
│         │         ms │      ms │        ms │         ms │           ms │                us │       MB │          % │
├─────────┼────────────┼─────────┼───────────┼────────────┼──────────────┼───────────────────┼──────────┼────────────┤
│ minimum │       2499 │     316 │       249 │         67 │          129 │                23 │     6977 │         13 │
│  median │       2504 │     319 │       251 │         67 │          130 │                24 │     6991 │         13 │
│ maximum │       2520 │     322 │       254 │         69 │          132 │                27 │     6997 │         13 │
│   stdev │          9 │       2 │         2 │          1 │            1 │                 2 │        9 │          0 │
└─────────┴────────────┴─────────┴───────────┴────────────┴──────────────┴───────────────────┴──────────┴────────────┘
category = "append"
bench = "append.jl"
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
┌─────────┬────────────┬─────────┬───────────┬────────────┬──────────────┬───────────────────┬──────────┬────────────┐
│         │ total time │ gc time │ mark time │ sweep time │ max GC pause │ time to safepoint │ max heap │ percent gc │
│         │         ms │      ms │        ms │         ms │           ms │                us │       MB │          % │
├─────────┼────────────┼─────────┼───────────┼────────────┼──────────────┼───────────────────┼──────────┼────────────┤
│ minimum │        848 │     272 │       179 │         90 │           64 │                81 │     4036 │         32 │
│  median │        854 │     273 │       181 │         92 │           65 │                86 │     4036 │         32 │
│ maximum │        859 │     275 │       182 │         96 │           67 │               101 │     4036 │         32 │
│   stdev │          4 │       2 │         1 │          2 │            1 │                 8 │        0 │          0 │
└─────────┴────────────┴─────────┴───────────┴────────────┴──────────────┴───────────────────┴──────────┴────────────┘
category = "big_arrays"
bench = "many_refs.jl"
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
┌─────────┬────────────┬─────────┬───────────┬────────────┬──────────────┬───────────────────┬──────────┬────────────┐
│         │ total time │ gc time │ mark time │ sweep time │ max GC pause │ time to safepoint │ max heap │ percent gc │
│         │         ms │      ms │        ms │         ms │           ms │                us │       MB │          % │
├─────────┼────────────┼─────────┼───────────┼────────────┼──────────────┼───────────────────┼──────────┼────────────┤
│ minimum │       1120 │     884 │       825 │         58 │          291 │                12 │      875 │         79 │
│  median │       1132 │     893 │       834 │         59 │          298 │                13 │      876 │         79 │
│ maximum │       1156 │     909 │       850 │         60 │          301 │                18 │      877 │         79 │
│   stdev │         15 │      12 │        11 │          1 │            4 │                 3 │        1 │          0 │
└─────────┴────────────┴─────────┴───────────┴────────────┴──────────────┴───────────────────┴──────────┴────────────┘
bench = "single_ref.jl"
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
┌─────────┬────────────┬─────────┬───────────┬────────────┬──────────────┬───────────────────┬──────────┬────────────┐
│         │ total time │ gc time │ mark time │ sweep time │ max GC pause │ time to safepoint │ max heap │ percent gc │
│         │         ms │      ms │        ms │         ms │           ms │                us │       MB │          % │
├─────────┼────────────┼─────────┼───────────┼────────────┼──────────────┼───────────────────┼──────────┼────────────┤
│ minimum │        479 │     343 │       333 │         10 │          126 │                17 │      875 │         71 │
│  median │        481 │     344 │       334 │         10 │          126 │                18 │      877 │         72 │
│ maximum │        491 │     353 │       344 │         10 │          131 │                26 │      877 │         72 │
│   stdev │          5 │       4 │         4 │          0 │            2 │                 4 │        1 │          0 │
└─────────┴────────────┴─────────┴───────────┴────────────┴──────────────┴───────────────────┴──────────┴────────────┘
category = "bigint"
bench = "pollard.jl"
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
┌─────────┬────────────┬─────────┬───────────┬────────────┬──────────────┬───────────────────┬──────────┬────────────┐
│         │ total time │ gc time │ mark time │ sweep time │ max GC pause │ time to safepoint │ max heap │ percent gc │
│         │         ms │      ms │        ms │         ms │           ms │                us │       MB │          % │
├─────────┼────────────┼─────────┼───────────┼────────────┼──────────────┼───────────────────┼──────────┼────────────┤
│ minimum │        445 │     112 │       101 │         11 │           48 │                50 │      145 │         24 │
│  median │        464 │     118 │       107 │         11 │           48 │                58 │      146 │         25 │
│ maximum │        479 │     119 │       107 │         11 │           50 │                63 │      147 │         26 │
│   stdev │         14 │       3 │         3 │          0 │            1 │                 5 │        1 │          1 │
└─────────┴────────────┴─────────┴───────────┴────────────┴──────────────┴───────────────────┴──────────┴────────────┘
category = "linked"
bench = "list.jl"
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
┌─────────┬────────────┬─────────┬───────────┬────────────┬──────────────┬───────────────────┬──────────┬────────────┐
│         │ total time │ gc time │ mark time │ sweep time │ max GC pause │ time to safepoint │ max heap │ percent gc │
│         │         ms │      ms │        ms │         ms │           ms │                us │       MB │          % │
├─────────┼────────────┼─────────┼───────────┼────────────┼──────────────┼───────────────────┼──────────┼────────────┤
│ minimum │       3192 │    2540 │      2297 │        243 │         1030 │                65 │     3329 │         80 │
│  median │       3211 │    2564 │      2319 │        244 │         1035 │                69 │     3332 │         80 │
│ maximum │       3243 │    2590 │      2346 │        248 │         1038 │                81 │     3341 │         80 │
│   stdev │         19 │      18 │        18 │          2 │            3 │                 7 │        5 │          0 │
└─────────┴────────────┴─────────┴───────────┴────────────┴──────────────┴───────────────────┴──────────┴────────────┘
bench = "tree.jl"
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
┌─────────┬────────────┬─────────┬───────────┬────────────┬──────────────┬───────────────────┬──────────┬────────────┐
│         │ total time │ gc time │ mark time │ sweep time │ max GC pause │ time to safepoint │ max heap │ percent gc │
│         │         ms │      ms │        ms │         ms │           ms │                us │       MB │          % │
├─────────┼────────────┼─────────┼───────────┼────────────┼──────────────┼───────────────────┼──────────┼────────────┤
│ minimum │       6283 │     377 │       370 │          6 │          294 │                21 │      196 │          6 │
│  median │       6299 │     382 │       376 │          6 │          298 │                23 │      197 │          6 │
│ maximum │       6335 │     388 │       382 │          7 │          301 │                28 │      197 │          6 │
│   stdev │         20 │       4 │         4 │          0 │            3 │                 3 │        0 │          0 │
└─────────┴────────────┴─────────┴───────────┴────────────┴──────────────┴───────────────────┴──────────┴────────────┘
category = "strings"
bench = "strings.jl"
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
┌─────────┬────────────┬─────────┬───────────┬────────────┬──────────────┬───────────────────┬──────────┬────────────┐
│         │ total time │ gc time │ mark time │ sweep time │ max GC pause │ time to safepoint │ max heap │ percent gc │
│         │         ms │      ms │        ms │         ms │           ms │                us │       MB │          % │
├─────────┼────────────┼─────────┼───────────┼────────────┼──────────────┼───────────────────┼──────────┼────────────┤
│ minimum │      14520 │    2047 │      1843 │        202 │          706 │                83 │      762 │         14 │
│  median │      14579 │    2086 │      1882 │        203 │          718 │                87 │      766 │         14 │
│ maximum │      14908 │    2103 │      1896 │        207 │          731 │               101 │      778 │         14 │
│   stdev │        156 │      26 │        24 │          2 │           10 │                 8 │        6 │          0 │
└─────────┴────────────┴─────────┴───────────┴────────────┴──────────────┴───────────────────┴──────────┴────────────┘
category = "big_arrays"
bench = "issue-52937.jl"
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
┌─────────┬────────────┬─────────┬───────────┬────────────┬──────────────┬───────────────────┬──────────┬────────────┐
│         │ total time │ gc time │ mark time │ sweep time │ max GC pause │ time to safepoint │ max heap │ percent gc │
│         │         ms │      ms │        ms │         ms │           ms │                us │       MB │          % │
├─────────┼────────────┼─────────┼───────────┼────────────┼──────────────┼───────────────────┼──────────┼────────────┤
│ minimum │       5201 │    1029 │       482 │        546 │           13 │             99714 │      168 │         19 │
│  median │       5291 │    1043 │       496 │        554 │           13 │            107124 │      169 │         20 │
│ maximum │       5344 │    1092 │       523 │        575 │           15 │            116900 │      170 │         21 │
│   stdev │         54 │      30 │        18 │         13 │            1 │              6214 │        1 │          0 │
└─────────┴────────────┴─────────┴───────────┴────────────┴──────────────┴───────────────────┴──────────┴────────────┘
bench = "objarray.jl"
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
┌─────────┬────────────┬─────────┬───────────┬────────────┬──────────────┬───────────────────┬──────────┬────────────┐
│         │ total time │ gc time │ mark time │ sweep time │ max GC pause │ time to safepoint │ max heap │ percent gc │
│         │         ms │      ms │        ms │         ms │           ms │                us │       MB │          % │
├─────────┼────────────┼─────────┼───────────┼────────────┼──────────────┼───────────────────┼──────────┼────────────┤
│ minimum │       6463 │    3654 │      2723 │        912 │          547 │             19917 │     7915 │         56 │
│  median │       6607 │    3824 │      2860 │        964 │          578 │             23196 │     8316 │         58 │
│ maximum │       6668 │    3839 │      2873 │        979 │          662 │             56026 │     9877 │         58 │
│   stdev │         93 │      96 │        70 │         28 │           45 │             15407 │      760 │          1 │
└─────────┴────────────┴─────────┴───────────┴────────────┴──────────────┴───────────────────┴──────────┴────────────┘
category = "binary_tree"
bench = "tree_immutable.jl"
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
┌─────────┬────────────┬─────────┬───────────┬────────────┬──────────────┬───────────────────┬──────────┬────────────┐
│         │ total time │ gc time │ mark time │ sweep time │ max GC pause │ time to safepoint │ max heap │ percent gc │
│         │         ms │      ms │        ms │         ms │           ms │                us │       MB │          % │
├─────────┼────────────┼─────────┼───────────┼────────────┼──────────────┼───────────────────┼──────────┼────────────┤
│ minimum │       2264 │    1255 │       695 │        553 │           36 │              4454 │      381 │         55 │
│  median │       2289 │    1289 │       717 │        561 │           39 │              4787 │      411 │         56 │
│ maximum │       2296 │    1295 │       742 │        575 │           41 │              5243 │      418 │         57 │
│   stdev │         12 │      17 │        18 │          9 │            2 │               281 │       15 │          1 │
└─────────┴────────────┴─────────┴───────────┴────────────┴──────────────┴───────────────────┴──────────┴────────────┘
bench = "tree_mutable.jl"
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
┌─────────┬────────────┬─────────┬───────────┬────────────┬──────────────┬───────────────────┬──────────┬────────────┐
│         │ total time │ gc time │ mark time │ sweep time │ max GC pause │ time to safepoint │ max heap │ percent gc │
│         │         ms │      ms │        ms │         ms │           ms │                us │       MB │          % │
├─────────┼────────────┼─────────┼───────────┼────────────┼──────────────┼───────────────────┼──────────┼────────────┤
│ minimum │       3918 │    2449 │      1116 │       1332 │           57 │              5403 │      695 │         62 │
│  median │       4005 │    2532 │      1144 │       1359 │           59 │              5865 │      707 │         63 │
│ maximum │       4056 │    2549 │      1199 │       1397 │           62 │              6031 │      736 │         63 │
│   stdev │         57 │      40 │        31 │         28 │            2 │               248 │       16 │          0 │
└─────────┴────────────┴─────────┴───────────┴────────────┴──────────────┴───────────────────┴──────────┴────────────┘
category = "mergesort_parallel"
bench = "mergesort_parallel.jl"
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
┌─────────┬────────────┬─────────┬───────────┬────────────┬──────────────┬───────────────────┬──────────┬────────────┐
│         │ total time │ gc time │ mark time │ sweep time │ max GC pause │ time to safepoint │ max heap │ percent gc │
│         │         ms │      ms │        ms │         ms │           ms │                us │       MB │          % │
├─────────┼────────────┼─────────┼───────────┼────────────┼──────────────┼───────────────────┼──────────┼────────────┤
│ minimum │       2185 │     448 │       273 │        175 │           52 │              1227 │     1235 │         21 │
│  median │       2250 │     504 │       285 │        209 │           55 │              1301 │     1249 │         22 │
│ maximum │       2260 │     528 │       318 │        218 │           79 │              1487 │     1336 │         23 │
│   stdev │         31 │      31 │        17 │         18 │           11 │               111 │       47 │          1 │
└─────────┴────────────┴─────────┴───────────┴────────────┴──────────────┴───────────────────┴──────────┴────────────┘
category = "mm_divide_and_conquer"
bench = "mm_divide_and_conquer.jl"
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
┌─────────┬────────────┬─────────┬───────────┬────────────┬──────────────┬───────────────────┬──────────┬────────────┐
│         │ total time │ gc time │ mark time │ sweep time │ max GC pause │ time to safepoint │ max heap │ percent gc │
│         │         ms │      ms │        ms │         ms │           ms │                us │       MB │          % │
├─────────┼────────────┼─────────┼───────────┼────────────┼──────────────┼───────────────────┼──────────┼────────────┤
│ minimum │        503 │      85 │        58 │         25 │           14 │             57337 │     2361 │         17 │
│  median │        507 │      86 │        61 │         26 │           15 │             59871 │     2379 │         17 │
│ maximum │        524 │      89 │        64 │         26 │           16 │             63875 │     2600 │         17 │
│   stdev │          8 │       2 │         2 │          0 │            1 │              2362 │      101 │          0 │
└─────────┴────────────┴─────────┴───────────┴────────────┴──────────────┴───────────────────┴──────────┴────────────┘

PR:

category = "TimeZones"
bench = "TimeZones.jl"
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
┌─────────┬────────────┬─────────┬───────────┬────────────┬──────────────┬───────────────────┬──────────┬────────────┐
│         │ total time │ gc time │ mark time │ sweep time │ max GC pause │ time to safepoint │ max heap │ percent gc │
│         │         ms │      ms │        ms │         ms │           ms │                us │       MB │          % │
├─────────┼────────────┼─────────┼───────────┼────────────┼──────────────┼───────────────────┼──────────┼────────────┤
│ minimum │       2490 │     322 │       247 │         73 │          135 │                19 │     6994 │         13 │
│  median │       2510 │     322 │       249 │         75 │          137 │                24 │     6999 │         13 │
│ maximum │       2525 │     329 │       254 │         75 │          139 │                25 │     7022 │         13 │
│   stdev │         12 │       3 │         3 │          1 │            1 │                 3 │       13 │          0 │
└─────────┴────────────┴─────────┴───────────┴────────────┴──────────────┴───────────────────┴──────────┴────────────┘
category = "append"
bench = "append.jl"
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
┌─────────┬────────────┬─────────┬───────────┬────────────┬──────────────┬───────────────────┬──────────┬────────────┐
│         │ total time │ gc time │ mark time │ sweep time │ max GC pause │ time to safepoint │ max heap │ percent gc │
│         │         ms │      ms │        ms │         ms │           ms │                us │       MB │          % │
├─────────┼────────────┼─────────┼───────────┼────────────┼──────────────┼───────────────────┼──────────┼────────────┤
│ minimum │        865 │     275 │       179 │         93 │           65 │                85 │     4036 │         32 │
│  median │        868 │     278 │       182 │         96 │           66 │                88 │     4036 │         32 │
│ maximum │        890 │     287 │       191 │         99 │           67 │               102 │     4036 │         32 │
│   stdev │         10 │       4 │         4 │          2 │            1 │                 7 │        0 │          0 │
└─────────┴────────────┴─────────┴───────────┴────────────┴──────────────┴───────────────────┴──────────┴────────────┘
category = "big_arrays"
bench = "many_refs.jl"
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
┌─────────┬────────────┬─────────┬───────────┬────────────┬──────────────┬───────────────────┬──────────┬────────────┐
│         │ total time │ gc time │ mark time │ sweep time │ max GC pause │ time to safepoint │ max heap │ percent gc │
│         │         ms │      ms │        ms │         ms │           ms │                us │       MB │          % │
├─────────┼────────────┼─────────┼───────────┼────────────┼──────────────┼───────────────────┼──────────┼────────────┤
│ minimum │       1130 │     893 │       835 │         58 │          296 │                12 │      875 │         79 │
│  median │       1135 │     896 │       837 │         59 │          298 │                12 │      877 │         79 │
│ maximum │       1139 │     898 │       839 │         59 │          299 │                15 │      878 │         79 │
│   stdev │          4 │       2 │         2 │          0 │            1 │                 1 │        1 │          0 │
└─────────┴────────────┴─────────┴───────────┴────────────┴──────────────┴───────────────────┴──────────┴────────────┘
bench = "single_ref.jl"
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
┌─────────┬────────────┬─────────┬───────────┬────────────┬──────────────┬───────────────────┬──────────┬────────────┐
│         │ total time │ gc time │ mark time │ sweep time │ max GC pause │ time to safepoint │ max heap │ percent gc │
│         │         ms │      ms │        ms │         ms │           ms │                us │       MB │          % │
├─────────┼────────────┼─────────┼───────────┼────────────┼──────────────┼───────────────────┼──────────┼────────────┤
│ minimum │        480 │     342 │       333 │         10 │          125 │                17 │      877 │         71 │
│  median │        481 │     346 │       336 │         10 │          127 │                19 │      877 │         72 │
│ maximum │        487 │     350 │       340 │         10 │          128 │                21 │      877 │         72 │
│   stdev │          3 │       3 │         3 │          0 │            1 │                 1 │        0 │          0 │
└─────────┴────────────┴─────────┴───────────┴────────────┴──────────────┴───────────────────┴──────────┴────────────┘
category = "bigint"
bench = "pollard.jl"
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
┌─────────┬────────────┬─────────┬───────────┬────────────┬──────────────┬───────────────────┬──────────┬────────────┐
│         │ total time │ gc time │ mark time │ sweep time │ max GC pause │ time to safepoint │ max heap │ percent gc │
│         │         ms │      ms │        ms │         ms │           ms │                us │       MB │          % │
├─────────┼────────────┼─────────┼───────────┼────────────┼──────────────┼───────────────────┼──────────┼────────────┤
│ minimum │        463 │     116 │       105 │         11 │           47 │                47 │      145 │         25 │
│  median │        464 │     119 │       108 │         11 │           48 │                58 │      146 │         26 │
│ maximum │        475 │     119 │       108 │         11 │           49 │                64 │      147 │         26 │
│   stdev │          5 │       2 │         1 │          0 │            1 │                 6 │        1 │          1 │
└─────────┴────────────┴─────────┴───────────┴────────────┴──────────────┴───────────────────┴──────────┴────────────┘
category = "linked"
bench = "list.jl"
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
┌─────────┬────────────┬─────────┬───────────┬────────────┬──────────────┬───────────────────┬──────────┬────────────┐
│         │ total time │ gc time │ mark time │ sweep time │ max GC pause │ time to safepoint │ max heap │ percent gc │
│         │         ms │      ms │        ms │         ms │           ms │                us │       MB │          % │
├─────────┼────────────┼─────────┼───────────┼────────────┼──────────────┼───────────────────┼──────────┼────────────┤
│ minimum │       3219 │    2575 │      2334 │        242 │         1048 │                65 │     3328 │         80 │
│  median │       3233 │    2587 │      2344 │        244 │         1057 │                69 │     3331 │         80 │
│ maximum │       3244 │    2593 │      2348 │        246 │         1058 │                70 │     3334 │         80 │
│   stdev │          9 │       7 │         6 │          2 │            4 │                 2 │        2 │          0 │
└─────────┴────────────┴─────────┴───────────┴────────────┴──────────────┴───────────────────┴──────────┴────────────┘
bench = "tree.jl"
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
┌─────────┬────────────┬─────────┬───────────┬────────────┬──────────────┬───────────────────┬──────────┬────────────┐
│         │ total time │ gc time │ mark time │ sweep time │ max GC pause │ time to safepoint │ max heap │ percent gc │
│         │         ms │      ms │        ms │         ms │           ms │                us │       MB │          % │
├─────────┼────────────┼─────────┼───────────┼────────────┼──────────────┼───────────────────┼──────────┼────────────┤
│ minimum │       6191 │     374 │       367 │          6 │          291 │                22 │      197 │          6 │
│  median │       6305 │     381 │       375 │          7 │          298 │                23 │      197 │          6 │
│ maximum │       6902 │     393 │       387 │          7 │          309 │                25 │      197 │          6 │
│   stdev │        285 │       8 │         8 │          0 │            7 │                 1 │        0 │          0 │
└─────────┴────────────┴─────────┴───────────┴────────────┴──────────────┴───────────────────┴──────────┴────────────┘
category = "strings"
bench = "strings.jl"
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
┌─────────┬────────────┬─────────┬───────────┬────────────┬──────────────┬───────────────────┬──────────┬────────────┐
│         │ total time │ gc time │ mark time │ sweep time │ max GC pause │ time to safepoint │ max heap │ percent gc │
│         │         ms │      ms │        ms │         ms │           ms │                us │       MB │          % │
├─────────┼────────────┼─────────┼───────────┼────────────┼──────────────┼───────────────────┼──────────┼────────────┤
│ minimum │      14558 │    2028 │      1826 │        201 │          717 │                82 │      757 │         14 │
│  median │      14672 │    2056 │      1852 │        203 │          722 │                88 │      764 │         14 │
│ maximum │      14877 │    2059 │      1854 │        205 │          728 │                93 │      767 │         14 │
│   stdev │        129 │      15 │        14 │          1 │            5 │                 5 │        4 │          0 │
└─────────┴────────────┴─────────┴───────────┴────────────┴──────────────┴───────────────────┴──────────┴────────────┘
category = "big_arrays"
bench = "issue-52937.jl"
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
┌─────────┬────────────┬─────────┬───────────┬────────────┬──────────────┬───────────────────┬──────────┬────────────┐
│         │ total time │ gc time │ mark time │ sweep time │ max GC pause │ time to safepoint │ max heap │ percent gc │
│         │         ms │      ms │        ms │         ms │           ms │                us │       MB │          % │
├─────────┼────────────┼─────────┼───────────┼────────────┼──────────────┼───────────────────┼──────────┼────────────┤
│ minimum │       5231 │    1062 │       505 │        548 │           15 │             99324 │      169 │         20 │
│  median │       5301 │    1068 │       514 │        552 │           16 │            102951 │      169 │         20 │
│ maximum │       5414 │    1111 │       545 │        578 │           18 │            110486 │      172 │         21 │
│   stdev │         69 │      21 │        15 │         13 │            1 │              4422 │        1 │          0 │
└─────────┴────────────┴─────────┴───────────┴────────────┴──────────────┴───────────────────┴──────────┴────────────┘
bench = "objarray.jl"
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
┌─────────┬────────────┬─────────┬───────────┬────────────┬──────────────┬───────────────────┬──────────┬────────────┐
│         │ total time │ gc time │ mark time │ sweep time │ max GC pause │ time to safepoint │ max heap │ percent gc │
│         │         ms │      ms │        ms │         ms │           ms │                us │       MB │          % │
├─────────┼────────────┼─────────┼───────────┼────────────┼──────────────┼───────────────────┼──────────┼────────────┤
│ minimum │       6437 │    3611 │      2681 │        931 │          527 │             17693 │     7887 │         55 │
│  median │       6670 │    3804 │      2842 │        962 │          596 │             21943 │     8247 │         58 │
│ maximum │       6858 │    3973 │      2987 │        986 │          676 │             59174 │    10130 │         59 │
│   stdev │        163 │     131 │       113 │         20 │           58 │             16963 │      899 │          1 │
└─────────┴────────────┴─────────┴───────────┴────────────┴──────────────┴───────────────────┴──────────┴────────────┘
category = "binary_tree"
bench = "tree_immutable.jl"
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
┌─────────┬────────────┬─────────┬───────────┬────────────┬──────────────┬───────────────────┬──────────┬────────────┐
│         │ total time │ gc time │ mark time │ sweep time │ max GC pause │ time to safepoint │ max heap │ percent gc │
│         │         ms │      ms │        ms │         ms │           ms │                us │       MB │          % │
├─────────┼────────────┼─────────┼───────────┼────────────┼──────────────┼───────────────────┼──────────┼────────────┤
│ minimum │       2234 │    1247 │       655 │        558 │           36 │              4340 │      401 │         55 │
│  median │       2258 │    1268 │       709 │        566 │           38 │              4792 │      412 │         56 │
│ maximum │       2294 │    1276 │       714 │        592 │           39 │              4995 │      421 │         57 │
│   stdev │         23 │      13 │        25 │         13 │            1 │               259 │        8 │          1 │
└─────────┴────────────┴─────────┴───────────┴────────────┴──────────────┴───────────────────┴──────────┴────────────┘
bench = "tree_mutable.jl"
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
┌─────────┬────────────┬─────────┬───────────┬────────────┬──────────────┬───────────────────┬──────────┬────────────┐
│         │ total time │ gc time │ mark time │ sweep time │ max GC pause │ time to safepoint │ max heap │ percent gc │
│         │         ms │      ms │        ms │         ms │           ms │                us │       MB │          % │
├─────────┼────────────┼─────────┼───────────┼────────────┼──────────────┼───────────────────┼──────────┼────────────┤
│ minimum │       3923 │    2437 │      1099 │       1324 │           56 │              5610 │      704 │         62 │
│  median │       4055 │    2503 │      1136 │       1380 │           57 │              5784 │      718 │         62 │
│ maximum │       4093 │    2590 │      1150 │       1453 │           59 │              5974 │      732 │         63 │
│   stdev │         71 │      57 │        21 │         48 │            1 │               129 │       11 │          1 │
└─────────┴────────────┴─────────┴───────────┴────────────┴──────────────┴───────────────────┴──────────┴────────────┘
category = "mergesort_parallel"
bench = "mergesort_parallel.jl"
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
┌─────────┬────────────┬─────────┬───────────┬────────────┬──────────────┬───────────────────┬──────────┬────────────┐
│         │ total time │ gc time │ mark time │ sweep time │ max GC pause │ time to safepoint │ max heap │ percent gc │
│         │         ms │      ms │        ms │         ms │           ms │                us │       MB │          % │
├─────────┼────────────┼─────────┼───────────┼────────────┼──────────────┼───────────────────┼──────────┼────────────┤
│ minimum │       2152 │     442 │       272 │        170 │           43 │              1129 │     1187 │         21 │
│  median │       2240 │     503 │       297 │        207 │           55 │              1332 │     1247 │         23 │
│ maximum │       2281 │     527 │       311 │        216 │           57 │              1785 │     1300 │         23 │
│   stdev │         51 │      33 │        15 │         18 │            6 │               244 │       48 │          1 │
└─────────┴────────────┴─────────┴───────────┴────────────┴──────────────┴───────────────────┴──────────┴────────────┘
category = "mm_divide_and_conquer"
bench = "mm_divide_and_conquer.jl"
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
[ Info: Setting GC memory pressure callback
┌─────────┬────────────┬─────────┬───────────┬────────────┬──────────────┬───────────────────┬──────────┬────────────┐
│         │ total time │ gc time │ mark time │ sweep time │ max GC pause │ time to safepoint │ max heap │ percent gc │
│         │         ms │      ms │        ms │         ms │           ms │                us │       MB │          % │
├─────────┼────────────┼─────────┼───────────┼────────────┼──────────────┼───────────────────┼──────────┼────────────┤
│ minimum │        501 │      87 │        60 │         25 │           12 │             56704 │     2238 │         17 │
│  median │        508 │      89 │        61 │         27 │           13 │             62814 │     2463 │         18 │
│ maximum │        512 │      90 │        65 │         28 │           13 │             66117 │     2545 │         18 │
│   stdev │          4 │       1 │         2 │          1 │            0 │              3691 │      117 │          0 │
└─────────┴────────────┴─────────┴───────────┴────────────┴──────────────┴───────────────────┴──────────┴────────────┘

d-netto · 2024-07-12T13:30:37Z

We also ran our internal benchmarks and it looks fine performance-wise.

Could you take a look at the PR @gbaraldi, @vtjnash?

kpamnany

Nice. Some more comments would be great.

src/gc.h

Co-authored-by: Kiran Pamnany <kpamnany@users.noreply.github.com>

They should have been deleted in #54936, but were not.

Simplifies the layout of the doubly linked list of big objects to make it a bit more canonical: let's just store a pointer to the previous element, instead of storing a "pointer to the next element of the previous element". This should make the implementation a bit easier to understand without incurring any memory overhead. I ran the serial and multithreaded benchmarks from GCBenchmarks and this seems fairly close to performance neutral on my machine. We also ran our internal benchmarks on it at RAI and it looks fine from a correctness and performance point of view. --------- Co-authored-by: Kiran Pamnany <kpamnany@users.noreply.github.com>

They should have been deleted in JuliaLang#54936, but were not.

Simplifies the layout of the doubly linked list of big objects to make it a bit more canonical: let's just store a pointer to the previous element, instead of storing a "pointer to the next element of the previous element". This should make the implementation a bit easier to understand without incurring any memory overhead. I ran the serial and multithreaded benchmarks from GCBenchmarks and this seems fairly close to performance neutral on my machine. We also ran our internal benchmarks on it at RAI and it looks fine from a correctness and performance point of view. --------- Co-authored-by: Kiran Pamnany <kpamnany@users.noreply.github.com>

They should have been deleted in JuliaLang#54936, but were not.

Simplifies the layout of the doubly linked list of big objects to make it a bit more canonical: let's just store a pointer to the previous element, instead of storing a "pointer to the next element of the previous element". This should make the implementation a bit easier to understand without incurring any memory overhead. I ran the serial and multithreaded benchmarks from GCBenchmarks and this seems fairly close to performance neutral on my machine. We also ran our internal benchmarks on it at RAI and it looks fine from a correctness and performance point of view. --------- Co-authored-by: Kiran Pamnany <kpamnany@users.noreply.github.com>

They should have been deleted in JuliaLang#54936, but were not.

d-netto added the GC Garbage collector label Jun 26, 2024

d-netto requested review from vtjnash and gbaraldi June 26, 2024 02:57

d-netto marked this pull request as draft June 26, 2024 03:06

d-netto force-pushed the dcn-sweep-bigvals branch 3 times, most recently from 8020759 to a271d93 Compare June 26, 2024 03:55

d-netto force-pushed the dcn-sweep-bigvals branch 17 times, most recently from 1b7041f to 3ad2b27 Compare June 27, 2024 14:56

d-netto force-pushed the dcn-sweep-bigvals branch 3 times, most recently from f1c762c to 64b1fe4 Compare June 28, 2024 16:27

d-netto force-pushed the dcn-sweep-bigvals branch 6 times, most recently from c5b9e75 to 4b333ab Compare July 10, 2024 18:34

d-netto marked this pull request as ready for review July 10, 2024 19:04

d-netto force-pushed the dcn-sweep-bigvals branch from 4b333ab to 1d67c6f Compare July 10, 2024 20:14

d-netto mentioned this pull request Jul 11, 2024

test performance of upstream linked list PR RelationalAI/julia#166

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d-netto requested a review from kpamnany July 12, 2024 16:53

d-netto force-pushed the dcn-sweep-bigvals branch 2 times, most recently from ca573db to 2ad22b9 Compare July 14, 2024 15:54

kpamnany approved these changes Jul 15, 2024

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d-netto force-pushed the dcn-sweep-bigvals branch from 9ac935c to 66fe70a Compare July 15, 2024 16:19

d-netto and others added 2 commits July 15, 2024 15:18

simplify layout of bigvals

e9415ea

Add a few more comments

31ccd72

Co-authored-by: Kiran Pamnany <kpamnany@users.noreply.github.com>

d-netto force-pushed the dcn-sweep-bigvals branch from 66fe70a to 31ccd72 Compare July 15, 2024 18:18

d-netto merged commit f8bec45 into master Jul 15, 2024
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d-netto deleted the dcn-sweep-bigvals branch July 15, 2024 22:20

d-netto mentioned this pull request Jul 15, 2024

delete some unused fields of jl_gc_mark_cache_t #55138

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d-netto added a commit that referenced this pull request Jul 16, 2024

delete some unused fields of jl_gc_mark_cache_t (#55138)

17668e9

They should have been deleted in #54936, but were not.

d-netto added a commit to RelationalAI/julia that referenced this pull request Jul 22, 2024

delete some unused fields of jl_gc_mark_cache_t (JuliaLang#55138)

a0d1872

They should have been deleted in JuliaLang#54936, but were not.

d-netto mentioned this pull request Jul 22, 2024

Bring a few upstream GC patches into our fork RelationalAI/julia#169

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d-netto added a commit to RelationalAI/julia that referenced this pull request Jul 25, 2024

delete some unused fields of jl_gc_mark_cache_t (JuliaLang#55138)

7ae4e32

They should have been deleted in JuliaLang#54936, but were not.

nickrobinson251 pushed a commit to RelationalAI/julia that referenced this pull request Feb 26, 2025

delete some unused fields of jl_gc_mark_cache_t (JuliaLang#55138)

5c66ffe

They should have been deleted in JuliaLang#54936, but were not.

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