Commit 6546b19f authored by Namhyung Kim's avatar Namhyung Kim Committed by Arnaldo Carvalho de Melo
Browse files

perf/core: Add PERF_SAMPLE_CGROUP feature 



The PERF_SAMPLE_CGROUP bit is to save (perf_event) cgroup information in
the sample.  It will add a 64-bit id to identify current cgroup and it's
the file handle in the cgroup file system.  Userspace should use this
information with PERF_RECORD_CGROUP event to match which cgroup it
belongs.

I put it before PERF_SAMPLE_AUX for simplicity since it just needs a
64-bit word.  But if we want bigger samples, I can work on that
direction too.

Committer testing:

  $ pahole perf_sample_data | grep -w cgroup -B5 -A5
  	/* --- cacheline 4 boundary (256 bytes) was 56 bytes ago --- */
  	struct perf_regs           regs_intr;            /*   312    16 */
  	/* --- cacheline 5 boundary (320 bytes) was 8 bytes ago --- */
  	u64                        stack_user_size;      /*   328     8 */
  	u64                        phys_addr;            /*   336     8 */
  	u64                        cgroup;               /*   344     8 */

  	/* size: 384, cachelines: 6, members: 22 */
  	/* padding: 32 */
  };
  $

Signed-off-by: default avatarNamhyung Kim <namhyung@kernel.org>
Tested-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: default avatarTejun Heo <tj@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Zefan Li <lizefan@huawei.com>
Link: http://lore.kernel.org/lkml/20200325124536.2800725-3-namhyung@kernel.org


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 96aaab68

include/linux/perf_event.h

+1 −0
Original line number Diff line number Diff line
@@ -1020,6 +1020,7 @@ struct perf_sample_data { 
	u64				stack_user_size;



	u64				phys_addr;

	u64				cgroup;

} ____cacheline_aligned;



/* default value for data source */

include/uapi/linux/perf_event.h

+2 −1
Original line number Diff line number Diff line
@@ -142,8 +142,9 @@ enum perf_event_sample_format { 
	PERF_SAMPLE_REGS_INTR			= 1U << 18,

	PERF_SAMPLE_PHYS_ADDR			= 1U << 19,

	PERF_SAMPLE_AUX				= 1U << 20,

	PERF_SAMPLE_CGROUP			= 1U << 21,



	PERF_SAMPLE_MAX = 1U << 21,		/* non-ABI */

	PERF_SAMPLE_MAX = 1U << 22,		/* non-ABI */



	__PERF_SAMPLE_CALLCHAIN_EARLY		= 1ULL << 63, /* non-ABI; internal use */

};

init/Kconfig

+2 −1
Original line number Diff line number Diff line
@@ -1027,7 +1027,8 @@ config CGROUP_PERF 
	help

	  This option extends the perf per-cpu mode to restrict monitoring

	  to threads which belong to the cgroup specified and run on the

	  designated cpu.

	  designated cpu.  Or this can be used to have cgroup ID in samples

	  so that it can monitor performance events among cgroups.



	  Say N if unsure.

kernel/events/core.c

+22 −0
Original line number Diff line number Diff line
@@ -1862,6 +1862,9 @@ static void __perf_event_header_size(struct perf_event *event, u64 sample_type) 
	if (sample_type & PERF_SAMPLE_PHYS_ADDR)

		size += sizeof(data->phys_addr);



	if (sample_type & PERF_SAMPLE_CGROUP)

		size += sizeof(data->cgroup);



	event->header_size = size;

}
@@ -6867,6 +6870,9 @@ void perf_output_sample(struct perf_output_handle *handle, 
	if (sample_type & PERF_SAMPLE_PHYS_ADDR)

		perf_output_put(handle, data->phys_addr);



	if (sample_type & PERF_SAMPLE_CGROUP)

		perf_output_put(handle, data->cgroup);



	if (sample_type & PERF_SAMPLE_AUX) {

		perf_output_put(handle, data->aux_size);
@@ -7066,6 +7072,16 @@ void perf_prepare_sample(struct perf_event_header *header, 
	if (sample_type & PERF_SAMPLE_PHYS_ADDR)

		data->phys_addr = perf_virt_to_phys(data->addr);



#ifdef CONFIG_CGROUP_PERF

	if (sample_type & PERF_SAMPLE_CGROUP) {

		struct cgroup *cgrp;



		/* protected by RCU */

		cgrp = task_css_check(current, perf_event_cgrp_id, 1)->cgroup;

		data->cgroup = cgroup_id(cgrp);

	}

#endif



	if (sample_type & PERF_SAMPLE_AUX) {

		u64 size;
@@ -11264,6 +11280,12 @@ static int perf_copy_attr(struct perf_event_attr __user *uattr, 


	if (attr->sample_type & PERF_SAMPLE_REGS_INTR)

		ret = perf_reg_validate(attr->sample_regs_intr);



#ifndef CONFIG_CGROUP_PERF

	if (attr->sample_type & PERF_SAMPLE_CGROUP)

		return -EINVAL;

#endif



out:

	return ret;

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