Commit 3bd5a5fc authored by Adrian Hunter's avatar Adrian Hunter Committed by Ingo Molnar
Browse files

perf tools: Add test for converting perf time to/from TSC 



The test uses the newly added cap_usr_time_zero and time_zero of
perf_event_mmap_page.  TSC from rdtsc is compared with the time
from 2 perf events.  The test passes if the calculated times are
all in the correct order.

Signed-off-by: default avatarAdrian Hunter <adrian.hunter@intel.com>
Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1372425741-1676-4-git-send-email-adrian.hunter@intel.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent c73deb6a

tools/perf/Makefile

+3 −0
Original line number Diff line number Diff line
@@ -389,6 +389,9 @@ LIB_OBJS += $(OUTPUT)tests/bp_signal.o 
LIB_OBJS += $(OUTPUT)tests/bp_signal_overflow.o

LIB_OBJS += $(OUTPUT)tests/task-exit.o

LIB_OBJS += $(OUTPUT)tests/sw-clock.o

ifeq ($(ARCH),x86)

LIB_OBJS += $(OUTPUT)tests/perf-time-to-tsc.o

endif



BUILTIN_OBJS += $(OUTPUT)builtin-annotate.o

BUILTIN_OBJS += $(OUTPUT)builtin-bench.o

tools/perf/arch/x86/Makefile

+2 −0
Original line number Diff line number Diff line
@@ -6,3 +6,5 @@ ifndef NO_LIBUNWIND 
LIB_OBJS += $(OUTPUT)arch/$(ARCH)/util/unwind.o

endif

LIB_OBJS += $(OUTPUT)arch/$(ARCH)/util/header.o

LIB_OBJS += $(OUTPUT)arch/$(ARCH)/util/tsc.o

LIB_H += arch/$(ARCH)/util/tsc.h

tools/perf/arch/x86/util/tsc.c

0 → 100644
+59 −0
Original line number Diff line number Diff line 
#include <stdbool.h>

#include <errno.h>



#include <linux/perf_event.h>



#include "../../perf.h"

#include "../../util/types.h"

#include "../../util/debug.h"

#include "tsc.h"



u64 perf_time_to_tsc(u64 ns, struct perf_tsc_conversion *tc)

{

	u64 time, quot, rem;



	time = ns - tc->time_zero;

	quot = time / tc->time_mult;

	rem  = time % tc->time_mult;

	return (quot << tc->time_shift) +

	       (rem << tc->time_shift) / tc->time_mult;

}



u64 tsc_to_perf_time(u64 cyc, struct perf_tsc_conversion *tc)

{

	u64 quot, rem;



	quot = cyc >> tc->time_shift;

	rem  = cyc & ((1 << tc->time_shift) - 1);

	return tc->time_zero + quot * tc->time_mult +

	       ((rem * tc->time_mult) >> tc->time_shift);

}



int perf_read_tsc_conversion(const struct perf_event_mmap_page *pc,

			     struct perf_tsc_conversion *tc)

{

	bool cap_usr_time_zero;

	u32 seq;

	int i = 0;



	while (1) {

		seq = pc->lock;

		rmb();

		tc->time_mult = pc->time_mult;

		tc->time_shift = pc->time_shift;

		tc->time_zero = pc->time_zero;

		cap_usr_time_zero = pc->cap_usr_time_zero;

		rmb();

		if (pc->lock == seq && !(seq & 1))

			break;

		if (++i > 10000) {

			pr_debug("failed to get perf_event_mmap_page lock\n");

			return -EINVAL;

		}

	}



	if (!cap_usr_time_zero)

		return -EOPNOTSUPP;



	return 0;

}

tools/perf/arch/x86/util/tsc.h

0 → 100644
+20 −0
Original line number Diff line number Diff line 
#ifndef TOOLS_PERF_ARCH_X86_UTIL_TSC_H__

#define TOOLS_PERF_ARCH_X86_UTIL_TSC_H__



#include "../../util/types.h"



struct perf_tsc_conversion {

	u16 time_shift;

	u32 time_mult;

	u64 time_zero;

};



struct perf_event_mmap_page;



int perf_read_tsc_conversion(const struct perf_event_mmap_page *pc,

			     struct perf_tsc_conversion *tc);



u64 perf_time_to_tsc(u64 ns, struct perf_tsc_conversion *tc);

u64 tsc_to_perf_time(u64 cyc, struct perf_tsc_conversion *tc);



#endif /* TOOLS_PERF_ARCH_X86_UTIL_TSC_H__ */

tools/perf/tests/builtin-test.c

+6 −0
Original line number Diff line number Diff line
@@ -93,6 +93,12 @@ static struct test { 
		.desc = "Test software clock events have valid period values",

		.func = test__sw_clock_freq,

	},

#if defined(__x86_64__) || defined(__i386__)

	{

		.desc = "Test converting perf time to TSC",

		.func = test__perf_time_to_tsc,

	},

#endif

	{

		.func = NULL,

	},

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