bpf: Speed up symbol resolving in kprobe multi link #2967
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Fully exporting kallsyms_on_each_symbol function, so it can be used in following changes. Rather than adding another ifdef option let's export the function completely (when CONFIG_KALLSYMS option is defined). Cc: Christoph Hellwig <hch@lst.de> Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Adding ftrace_lookup_symbols function that resolves array of symbols
with single pass over kallsyms.
The user provides array of string pointers with count and pointer to
allocated array for resolved values.
int ftrace_lookup_symbols(const char **sorted_syms, size_t cnt,
unsigned long *addrs)
It iterates all kallsyms symbols and tries to loop up each in provided
symbols array with bsearch. The symbols array needs to be sorted by
name for this reason.
We also check each symbol to pass ftrace_location, because this API
will be used for fprobe symbols resolving.
Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Using ftrace_lookup_symbols to speed up symbols lookup in register_fprobe_syms API. Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Using kallsyms_lookup_names function to speed up symbols lookup in
kprobe multi link attachment and replacing with it the current
kprobe_multi_resolve_syms function.
This speeds up bpftrace kprobe attachment:
# perf stat -r 5 -e cycles ./src/bpftrace -e 'kprobe:x* { } i:ms:1 { exit(); }'
...
6.5681 +- 0.0225 seconds time elapsed ( +- 0.34% )
After:
# perf stat -r 5 -e cycles ./src/bpftrace -e 'kprobe:x* { } i:ms:1 { exit(); }'
...
0.5661 +- 0.0275 seconds time elapsed ( +- 4.85% )
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Adding test that reads all functions from ftrace available_filter_functions file and attach them all through kprobe_multi API. It also prints stats info with -v option, like on my setup: test_bench_attach: found 48712 functions test_bench_attach: attached in 1.069s test_bench_attach: detached in 0.373s Acked-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Jiri Olsa <jolsa@kernel.org>
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Master branch: 20b87e7 |
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At least one diff in series https://patchwork.kernel.org/project/netdevbpf/list/?series=639391 expired. Closing PR. |
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Pull request for series with
subject: bpf: Speed up symbol resolving in kprobe multi link
version: 1
url: https://patchwork.kernel.org/project/netdevbpf/list/?series=639391