Commit 741b6c83 authored Jun 10, 2022 by Thomas Richter Committed by Greg Kroah-Hartman Jun 29, 2022

s390/cpumf: Handle events cycles and instructions identical



[ Upstream commit be857b7f77d130dbbd47c91fc35198b040f35865 ]

Events CPU_CYCLES and INSTRUCTIONS can be submitted with two different
perf_event attribute::type values:
 - PERF_TYPE_HARDWARE: when invoked via perf tool predefined events name
   cycles or cpu-cycles or instructions.
 - pmu->type: when invoked via perf tool event name cpu_cf/CPU_CYLCES/ or
   cpu_cf/INSTRUCTIONS/. This invocation also selects the PMU to which
   the event belongs.
Handle both type of invocations identical for events CPU_CYLCES and
INSTRUCTIONS. They address the same hardware.
The result is different when event modifier exclude_kernel is also set.
Invocation with event modifier for user space event counting fails.

Output before:

 # perf stat -e cpum_cf/cpu_cycles/u -- true

 Performance counter stats for 'true':

   <not supported>      cpum_cf/cpu_cycles/u

       0.000761033 seconds time elapsed

       0.000076000 seconds user
       0.000725000 seconds sys

 #

Output after:
 # perf stat -e cpum_cf/cpu_cycles/u -- true

 Performance counter stats for 'true':

           349,613      cpum_cf/cpu_cycles/u

       0.000844143 seconds time elapsed

       0.000079000 seconds user
       0.000800000 seconds sys
 #

Fixes: 6a82e23f45fe ("s390/cpumf: Adjust registration of s390 PMU device drivers")
Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Acked-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
[agordeev@linux.ibm.com corrected commit ID of Fixes commit]
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

parent 4837d1c8

arch/s390/kernel/perf_cpum_cf.c

+21 −1

Original line number	Original line	Diff line number	Diff line
	@@ -292,6 +292,26 @@ static int __hw_perf_event_init(struct perf_event *event, unsigned int type)
	return err;		return err;
	}		}

			/* Events CPU_CYLCES and INSTRUCTIONS can be submitted with two different
			* attribute::type values:
			* - PERF_TYPE_HARDWARE:
			* - pmu->type:
			* Handle both type of invocations identical. They address the same hardware.
			* The result is different when event modifiers exclude_kernel and/or
			* exclude_user are also set.
			*/
			static int cpumf_pmu_event_type(struct perf_event *event)
			{
			u64 ev = event->attr.config;

			if (cpumf_generic_events_basic[PERF_COUNT_HW_CPU_CYCLES] == ev \|\|
			cpumf_generic_events_basic[PERF_COUNT_HW_INSTRUCTIONS] == ev \|\|
			cpumf_generic_events_user[PERF_COUNT_HW_CPU_CYCLES] == ev \|\|
			cpumf_generic_events_user[PERF_COUNT_HW_INSTRUCTIONS] == ev)
			return PERF_TYPE_HARDWARE;
			return PERF_TYPE_RAW;
			}

	static int cpumf_pmu_event_init(struct perf_event *event)		static int cpumf_pmu_event_init(struct perf_event *event)
	{		{
	unsigned int type = event->attr.type;		unsigned int type = event->attr.type;
	@@ -301,7 +321,7 @@ static int cpumf_pmu_event_init(struct perf_event *event)
	err = __hw_perf_event_init(event, type);		err = __hw_perf_event_init(event, type);
	else if (event->pmu->type == type)		else if (event->pmu->type == type)
	/* Registered as unknown PMU */		/* Registered as unknown PMU */
	err = __hw_perf_event_init(event, PERF_TYPE_RAW);		err = __hw_perf_event_init(event, cpumf_pmu_event_type(event));
	else		else
	return -ENOENT;		return -ENOENT;