linux_perf_event: exclude_idle only on x86_64 #2295
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@scylladb/seastar-maint please consider merging |
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Doesn't it fix an open bug? |
| .exclude_idle = 1, | ||
| #endif |
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Where is it documented? Perhaps we should opt-in where it is supported?
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Also, need some comment, it looks completely obscure.
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EPERM Returned on many (but not all) architectures when an
unsupported exclude_hv, exclude_idle, exclude_user, or
exclude_kernel setting is specified.
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Since we've lived without it until 93f19d3 we can opt-in and include it only on x86_64 where we know it works (and add a comment about that)
The bug was opened in scylladb (scylladb/scylladb#19227) so updating the seastar submodule should be marked as fixing it. Edit: opened #2298 |
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Refactor the common code making linux_perf_event out of `user_instructions_retired` and `user_cpu_cycles_retired`. Signed-off-by: Benny Halevy <[email protected]>
Commit 93f19d3 added `exclude_idle = 1` to `linux_perf_event`. However, as reported in scylladb/scylladb#19227 (comment), `exclude_idle` is not supported on ARM platforms. This change sets `exclude_idle` only on known-to-work architectures (presently, it's only x86_64), assuming it is initialized to 0 as all other unset bitfields in `perf_event_attr`. Fixes scylladb#2298 Signed-off-by: Benny Halevy <[email protected]>
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Commit 93f19d3
added
exclude_idle = 1tolinux_perf_event.However, as reported in
scylladb/scylladb#19227 (comment),
exclude_idleis not supported on ARM platforms.This change sets
exclude_idleonly on known-to-work architectures(presently, it's only x86_64), assuming it is initialized to 0 as all
other unset bitfields in
perf_event_attr.Fixes #2298