Commit bc2373a5 authored by Kan Liang's avatar Kan Liang Committed by Arnaldo Carvalho de Melo
Browse files

perf tsc: Add arch TSC frequency information 



The TSC frequency information is required for the event metrics with the
literal, system_tsc_freq. For the newer Intel platform, the TSC
frequency information can be retrieved from the CPUID leaf 0x15.  If the
TSC frequency information isn't present the /proc/cpuinfo approach is
used.

Refactor cpuid() for this use. Note, the previous stack pushing/popping
approach was broken on x86-64 that has stack red zones that would be
clobbered.

Committer testing:

Before:

  $ perf record sleep 0.0001
  [ perf record: Woken up 1 times to write data ]
  $ perf report --header-only |& grep cpuid
  # cpuid : AuthenticAMD,25,33,0
  $

After the patch:

  $ perf record sleep 0.0001
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.002 MB perf.data (8 samples) ]
  $ perf report --header-only |& grep cpuid
  # cpuid : AuthenticAMD,25,33,0
  $

Signed-off-by: default avatarKan Liang <kan.liang@linux.intel.com>
Tested-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexandre Torgue <alexandre.torgue@foss.st.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Caleb Biggers <caleb.biggers@intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@arm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Garry <john.garry@huawei.com>
Cc: Kshipra Bopardikar <kshipra.bopardikar@intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Perry Taylor <perry.taylor@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Xing Zhengjun <zhengjun.xing@linux.intel.com>
Link: https://lore.kernel.org/r/20220718164312.3994191-2-irogers@google.com


Signed-off-by: default avatarIan Rogers <irogers@google.com>
Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 9fe9b252

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

0 → 100644
+34 −0
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0 */

#ifndef PERF_CPUID_H

#define PERF_CPUID_H 1





static inline void

cpuid(unsigned int op, unsigned int op2, unsigned int *a, unsigned int *b,

	unsigned int *c, unsigned int *d)

{

	/*

	 * Preserve %ebx/%rbx register by either placing it in %rdi or saving it

	 * on the stack - x86-64 needs to avoid the stack red zone. In PIC

	 * compilations %ebx contains the address of the global offset

	 * table. %rbx is occasionally used to address stack variables in

	 * presence of dynamic allocas.

	 */

	asm(

#if defined(__x86_64__)

		"mov %%rbx, %%rdi\n"

		"cpuid\n"

		"xchg %%rdi, %%rbx\n"

#else

		"pushl %%ebx\n"

		"cpuid\n"

		"movl %%ebx, %%edi\n"

		"popl %%ebx\n"

#endif

		: "=a"(*a), "=D"(*b), "=c"(*c), "=d"(*d)

		: "a"(op), "2"(op2));

}



void get_cpuid_0(char *vendor, unsigned int *lvl);



#endif

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

+11 −16
Original line number Diff line number Diff line
@@ -9,18 +9,17 @@ 


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

#include "../../../util/header.h"

#include "cpuid.h"



static inline void

cpuid(unsigned int op, unsigned int *a, unsigned int *b, unsigned int *c,

      unsigned int *d)

void get_cpuid_0(char *vendor, unsigned int *lvl)

{

	__asm__ __volatile__ (".byte 0x53\n\tcpuid\n\t"

			      "movl %%ebx, %%esi\n\t.byte 0x5b"

			: "=a" (*a),

			"=S" (*b),

			"=c" (*c),

			"=d" (*d)

			: "a" (op));

	unsigned int b, c, d;



	cpuid(0, 0, lvl, &b, &c, &d);

	strncpy(&vendor[0], (char *)(&b), 4);

	strncpy(&vendor[4], (char *)(&d), 4);

	strncpy(&vendor[8], (char *)(&c), 4);

	vendor[12] = '\0';

}



static int
@@ -31,14 +30,10 @@ __get_cpuid(char *buffer, size_t sz, const char *fmt) 
	int nb;

	char vendor[16];



	cpuid(0, &lvl, &b, &c, &d);

	strncpy(&vendor[0], (char *)(&b), 4);

	strncpy(&vendor[4], (char *)(&d), 4);

	strncpy(&vendor[8], (char *)(&c), 4);

	vendor[12] = '\0';

	get_cpuid_0(vendor, &lvl);



	if (lvl >= 1) {

		cpuid(1, &a, &b, &c, &d);

		cpuid(1, 0, &a, &b, &c, &d);



		family = (a >> 8) & 0xf;  /* bits 11 - 8 */

		model  = (a >> 4) & 0xf;  /* Bits  7 - 4 */

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

+33 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

#include <linux/types.h>

#include <string.h>



#include "../../../util/tsc.h"

#include "cpuid.h"



u64 rdtsc(void)

{
@@ -11,3 +13,34 @@ u64 rdtsc(void) 


	return low | ((u64)high) << 32;

}



double arch_get_tsc_freq(void)

{

	unsigned int a, b, c, d, lvl;

	static bool cached;

	static double tsc;

	char vendor[16];



	if (cached)

		return tsc;



	cached = true;

	get_cpuid_0(vendor, &lvl);

	if (!strstr(vendor, "Intel"))

		return 0;



	/*

	 * Don't support Time Stamp Counter and

	 * Nominal Core Crystal Clock Information Leaf.

	 */

	if (lvl < 0x15)

		return 0;



	cpuid(0x15, 0, &a, &b, &c, &d);

	/* TSC frequency is not enumerated */

	if (!a || !b || !c)

		return 0;



	tsc = (double)c * (double)b / (double)a;

	return tsc;

}

tools/perf/util/expr.c

+13 −0
Original line number Diff line number Diff line
@@ -12,6 +12,7 @@ 
#include "expr-bison.h"

#include "expr-flex.h"

#include "smt.h"

#include "tsc.h"

#include <linux/err.h>

#include <linux/kernel.h>

#include <linux/zalloc.h>
@@ -402,6 +403,13 @@ double expr_id_data__source_count(const struct expr_id_data *data) 
	return data->val.source_count;

}



#if !defined(__i386__) && !defined(__x86_64__)

double arch_get_tsc_freq(void)

{

	return 0.0;

}

#endif



double expr__get_literal(const char *literal)

{

	static struct cpu_topology *topology;
@@ -417,6 +425,11 @@ double expr__get_literal(const char *literal) 
		goto out;

	}



	if (!strcasecmp("#system_tsc_freq", literal)) {

		result = arch_get_tsc_freq();

		goto out;

	}



	/*

	 * Assume that topology strings are consistent, such as CPUs "0-1"

	 * wouldn't be listed as "0,1", and so after deduplication the number of

tools/perf/util/tsc.h

+1 −0
Original line number Diff line number Diff line
@@ -25,6 +25,7 @@ int perf_read_tsc_conversion(const struct perf_event_mmap_page *pc, 
u64 perf_time_to_tsc(u64 ns, struct perf_tsc_conversion *tc);

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

u64 rdtsc(void);

double arch_get_tsc_freq(void);



size_t perf_event__fprintf_time_conv(union perf_event *event, FILE *fp);