Commit fbc2844e authored by William Cohen's avatar William Cohen Committed by Arnaldo Carvalho de Melo
Browse files

perf vendor events: Use more flexible pattern matching for CPU identification for mapfile.csv 



The powerpc cpuid information includes chip revision information.
Changes between chip revisions are usually minor bug fixes and usually
do not affect the operation of the performance monitoring hardware.

The original mapfile.csv matching requires enumerating every possible
cpuid string.  When a new minor chip revision is produced a new entry
has to be added to the mapfile.csv and the code recompiled to allow perf
to have the implementation specific perf events for this new minor
revision.  For users of various distibutions of Linux having to wait for
a new release of the kernel's perf tool to be built with these trivial
patches is inconvenient.

Using regular expressions rather than exactly string matching of the
entire cpuid string allows developers to write mapfile.csv files that do
not require patches and recompiles for each of these minor version
changes.  If special cases need to be made for some particular versions,
they can be placed earlier in the mapfile.csv file before the more
general matches.

Signed-off-by: default avatarWilliam Cohen <wcohen@redhat.com>
Tested-by: default avatarRavi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Shriya <shriyak@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/20171204145728.16792-1-wcohen@redhat.com


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 01251952

tools/perf/pmu-events/arch/powerpc/mapfile.csv

+2 −10
Original line number Diff line number Diff line
@@ -13,13 +13,5 @@ 
#



# Power8 entries

004b0000,1,power8,core

004b0201,1,power8,core

004c0000,1,power8,core

004d0000,1,power8,core

004d0100,1,power8,core

004d0200,1,power8,core

004c0100,1,power8,core

004e0100,1,power9,core

004e0200,1,power9,core

004e1200,1,power9,core
 
004[bcd][[:xdigit:]]{4},1,power8,core

004e[[:xdigit:]]{4},1,power9,core

tools/perf/pmu-events/arch/x86/mapfile.csv

+1 −4
Original line number Diff line number Diff line
@@ -23,10 +23,7 @@ GenuineIntel-6-1E,v2,nehalemep,core 
GenuineIntel-6-1F,v2,nehalemep,core

GenuineIntel-6-1A,v2,nehalemep,core

GenuineIntel-6-2E,v2,nehalemex,core

GenuineIntel-6-4E,v24,skylake,core

GenuineIntel-6-5E,v24,skylake,core

GenuineIntel-6-8E,v24,skylake,core

GenuineIntel-6-9E,v24,skylake,core

GenuineIntel-6-[4589]E,v24,skylake,core

GenuineIntel-6-37,v13,silvermont,core

GenuineIntel-6-4D,v13,silvermont,core

GenuineIntel-6-4C,v13,silvermont,core

tools/perf/pmu-events/jevents.c

+38 −1
Original line number Diff line number Diff line
@@ -116,6 +116,43 @@ static void fixdesc(char *s) 
		*e = 0;

}



/* Add escapes for '\' so they are proper C strings. */

static char *fixregex(char *s)

{

	int len = 0;

	int esc_count = 0;

	char *fixed = NULL;

	char *p, *q;



	/* Count the number of '\' in string */

	for (p = s; *p; p++) {

		++len;

		if (*p == '\\')

			++esc_count;

	}



	if (esc_count == 0)

		return s;



	/* allocate space for a new string */

	fixed = (char *) malloc(len + 1);

	if (!fixed)

		return NULL;



	/* copy over the characters */

	q = fixed;

	for (p = s; *p; p++) {

		if (*p == '\\') {

			*q = '\\';

			++q;

		}

		*q = *p;

		++q;

	}

	*q = '\0';

	return fixed;

}



static struct msrmap {

	const char *num;

	const char *pname;
@@ -648,7 +685,7 @@ static int process_mapfile(FILE *outfp, char *fpath) 
		}

		line[strlen(line)-1] = '\0';



		cpuid = strtok_r(p, ",", &save);

		cpuid = fixregex(strtok_r(p, ",", &save));

		version = strtok_r(NULL, ",", &save);

		fname = strtok_r(NULL, ",", &save);

		type = strtok_r(NULL, ",", &save);

tools/perf/util/pmu.c

+19 −1
Original line number Diff line number Diff line
@@ -12,6 +12,7 @@ 
#include <dirent.h>

#include <api/fs/fs.h>

#include <locale.h>

#include <regex.h>

#include "util.h"

#include "pmu.h"

#include "parse-events.h"
@@ -609,15 +610,32 @@ struct pmu_events_map *perf_pmu__find_map(struct perf_pmu *pmu) 


	i = 0;

	for (;;) {

		regex_t re;

		regmatch_t pmatch[1];

		int match;



		map = &pmu_events_map[i++];

		if (!map->table) {

			map = NULL;

			break;

		}



		if (!strcmp(map->cpuid, cpuid))

		if (regcomp(&re, map->cpuid, REG_EXTENDED) != 0) {

			/* Warn unable to generate match particular string. */

			pr_info("Invalid regular expression %s\n", map->cpuid);

			break;

		}



		match = !regexec(&re, cpuid, 1, pmatch, 0);

		regfree(&re);

		if (match) {

			size_t match_len = (pmatch[0].rm_eo - pmatch[0].rm_so);



			/* Verify the entire string matched. */

			if (match_len == strlen(cpuid))

				break;

		}

	}

	free(cpuid);

	return map;

}

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