program: perform CO-RE against all kmod #1794
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The breaking change is renaming Cache.KernelModules, which hasn't been released yet. |
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@tpapagian could you give this PR a try against tetragon, with your work around to create a merged BTF removed? @brycekahle same for you, could you see how this fares for datadog agent? Thanks! |
Sure, will check that possibly tomorrow and I will let you know. |
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I'm seeing a lot of CO-RE errors like |
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OK. Those errors are happening on |
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@brycekahle mind filing a bug? |
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Things seems to work as expected in Tetragon using this PR and by removed the merged BTF code. Thanks! |
@lmb Will do. I was going to try and |
Accessing raw[0] is only valid if the length is > 0. Signed-off-by: Lorenz Bauer <lmb@isovalent.com>
CO-RE relocations are currently performed against vmlinux types only.
If a program attaches to a function in a kernel module we also
relocate against types in that module. This has the downside that
it's not possible to inspect a variable with a type defined in a
kernel module when tracing a function in vmlinux itself.
The historical reason for this is that our BTF parsing was quite
expensive. Now that we have lazy loading we can afford to relocate
against all types in the kernel.
Below is the change in performance against the last release:
core: 1
goos: linux
goarch: amd64
pkg: github.com/cilium/ebpf
cpu: 13th Gen Intel(R) Core(TM) i7-1365U
│ base.txt │ all.txt │
│ sec/op │ sec/op vs base │
NewCollectionManyProgs 336.94m ± 205% 16.38m ± 2% -95.14% (p=0.002 n=6)
│ base.txt │ all.txt │
│ B/op │ B/op vs base │
NewCollectionManyProgs 112.541Mi ± 45% 4.011Mi ± 0% -96.44% (p=0.002 n=6)
│ base.txt │ all.txt │
│ allocs/op │ allocs/op vs base │
NewCollectionManyProgs 386.00k ± 202% 39.78k ± 0% -89.70% (p=0.002 n=6)
Fixes: cilium#1511
Signed-off-by: Lorenz Bauer <lmb@isovalent.com>
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This fixes a long standing issue with our CO-RE implementation. Please see the commit message for details.