Messages in this thread | | | Subject | Re: [PATCH v2] sched/debug: Add new tracepoint to track cpu_capacity | From | Dietmar Eggemann <> | Date | Fri, 28 Aug 2020 19:10:41 +0200 |
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On 28/08/2020 12:27, Qais Yousef wrote: > On 08/28/20 10:00, vincent.donnefort@arm.com wrote: >> From: Vincent Donnefort <vincent.donnefort@arm.com> >> >> rq->cpu_capacity is a key element in several scheduler parts, such as EAS >> task placement and load balancing. Tracking this value enables testing >> and/or debugging by a toolkit. >> >> Signed-off-by: Vincent Donnefort <vincent.donnefort@arm.com> >> >> diff --git a/include/linux/sched.h b/include/linux/sched.h > > [...] > >> +int sched_trace_rq_cpu_capacity(struct rq *rq) >> +{ >> + return rq ? >> +#ifdef CONFIG_SMP >> + rq->cpu_capacity >> +#else >> + SCHED_CAPACITY_SCALE >> +#endif >> + : -1; >> +} >> +EXPORT_SYMBOL_GPL(sched_trace_rq_cpu_capacity); >> + > > The placement of this #ifdef looks odd to me. But FWIW > > Reviewed-by: Qais Yousef <qais.yousef@arm.com>
Returning -1 for cpu_capacity? It makes sense for sched_trace_rq_cpu() but for cpu_capacity?
Can you remind me why we have all these helper functions like sched_trace_rq_cpu_capacity?
In case we would let the extra code (which transforms trace points into trace events) know the internals of struct rq we could handle those things in the TRACE_EVENT and/or the register_trace_##name(void (*probe)(data_proto), void *data) thing. We always said when the internal things will change this extra code will break. So that's not an issue.
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