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| Started by | Mark Rutland <mark.rutland@arm.com> |
|---|---|
| First post | 2017-04-04 14:30 +0200 |
| Last post | 2017-04-05 11:30 +0200 |
| Articles | 2 — 2 participants |
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Re: [PATCH 2/3] perf tools arm64: implement function get_cpuid_str Mark Rutland <mark.rutland@arm.com> - 2017-04-04 14:30 +0200
Re: [PATCH 2/3] perf tools arm64: implement function get_cpuid_str Ganapatrao Kulkarni <gpkulkarni@gmail.com> - 2017-04-05 11:30 +0200
| From | Mark Rutland <mark.rutland@arm.com> |
|---|---|
| Date | 2017-04-04 14:30 +0200 |
| Subject | Re: [PATCH 2/3] perf tools arm64: implement function get_cpuid_str |
| Message-ID | <tsvKW-4O6-45@gated-at.bofh.it> |
On Tue, Apr 04, 2017 at 01:06:42PM +0530, Ganapatrao Kulkarni wrote:
> function get_cpuid_str returns midr_el1 value from first
> online cpu available.
This isn't globally the same (e.g. in big.LITTLE systems).
It would be far better to have the function take a PMU, and look at the
first CPU in that PMU's mask.
Thanks,
Mark.
>
> Signed-off-by: Ganapatrao Kulkarni <ganapatrao.kulkarni@cavium.com>
> ---
> tools/perf/arch/arm64/util/Build | 1 +
> tools/perf/arch/arm64/util/header.c | 51 +++++++++++++++++++++++++++++++++++++
> 2 files changed, 52 insertions(+)
> create mode 100644 tools/perf/arch/arm64/util/header.c
>
> diff --git a/tools/perf/arch/arm64/util/Build b/tools/perf/arch/arm64/util/Build
> index cef6fb3..b1ab72d 100644
> --- a/tools/perf/arch/arm64/util/Build
> +++ b/tools/perf/arch/arm64/util/Build
> @@ -1,3 +1,4 @@
> +libperf-y += header.o
> libperf-$(CONFIG_DWARF) += dwarf-regs.o
> libperf-$(CONFIG_LOCAL_LIBUNWIND) += unwind-libunwind.o
>
> diff --git a/tools/perf/arch/arm64/util/header.c b/tools/perf/arch/arm64/util/header.c
> new file mode 100644
> index 0000000..c0468fe
> --- /dev/null
> +++ b/tools/perf/arch/arm64/util/header.c
> @@ -0,0 +1,51 @@
> +#include <fnmatch.h>
> +#include <dirent.h>
> +#include <unistd.h>
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <string.h>
> +#include <linux/stringify.h>
> +#include "header.h"
> +#include "util.h"
> +
> +#define LINUX_SYS_CPU_DIRECTORY "/sys/devices/system/cpu/"
> +#define MIDR "/regs/identification/midr_el1"
> +
> +char *get_cpuid_str(void)
> +{
> + char *buf = malloc(128);
> + FILE *file;
> + char *ret = NULL;
> + int cpu , nr_cpu;
> + char sys_file[256];
> +
> + sprintf(sys_file, LINUX_SYS_CPU_DIRECTORY"kernel_max");
> +
> + file = fopen(sys_file, "r");
> + if (!file)
> + return ret;
> +
> + if (fscanf(file, "%d", &nr_cpu) != 1)
> + return ret;
> +
> + /* kernel_max returns nr_cpu -1 */
> + nr_cpu++;
> +
> + /*iterate till you read midr of first online cpu */
> + for(cpu = 0; cpu < nr_cpu; cpu++)
> + {
> + sprintf(sys_file, LINUX_SYS_CPU_DIRECTORY"cpu%d"MIDR, cpu);
> + file = fopen(sys_file, "r");
> + if (file) {
> + ret = fgets(buf, 128, file);
> + if (ret) {
> + buf[strlen(buf)-1] ='\0';
> + fclose(file);
> + return buf;
> + }
> + fclose(file);
> + }
> + }
> + free(buf);
> + return ret;
> +}
> --
> 1.8.1.4
>
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| From | Ganapatrao Kulkarni <gpkulkarni@gmail.com> |
|---|---|
| Date | 2017-04-05 11:30 +0200 |
| Message-ID | <tsPqi-Mk-13@gated-at.bofh.it> |
| In reply to | #1615976 |
On Tue, Apr 4, 2017 at 5:55 PM, Mark Rutland <mark.rutland@arm.com> wrote:
> On Tue, Apr 04, 2017 at 01:06:42PM +0530, Ganapatrao Kulkarni wrote:
>> function get_cpuid_str returns midr_el1 value from first
>> online cpu available.
>
> This isn't globally the same (e.g. in big.LITTLE systems).
>
> It would be far better to have the function take a PMU, and look at the
> first CPU in that PMU's mask.
thanks, will do.
>
> Thanks,
> Mark.
>
>>
>> Signed-off-by: Ganapatrao Kulkarni <ganapatrao.kulkarni@cavium.com>
>> ---
>> tools/perf/arch/arm64/util/Build | 1 +
>> tools/perf/arch/arm64/util/header.c | 51 +++++++++++++++++++++++++++++++++++++
>> 2 files changed, 52 insertions(+)
>> create mode 100644 tools/perf/arch/arm64/util/header.c
>>
>> diff --git a/tools/perf/arch/arm64/util/Build b/tools/perf/arch/arm64/util/Build
>> index cef6fb3..b1ab72d 100644
>> --- a/tools/perf/arch/arm64/util/Build
>> +++ b/tools/perf/arch/arm64/util/Build
>> @@ -1,3 +1,4 @@
>> +libperf-y += header.o
>> libperf-$(CONFIG_DWARF) += dwarf-regs.o
>> libperf-$(CONFIG_LOCAL_LIBUNWIND) += unwind-libunwind.o
>>
>> diff --git a/tools/perf/arch/arm64/util/header.c b/tools/perf/arch/arm64/util/header.c
>> new file mode 100644
>> index 0000000..c0468fe
>> --- /dev/null
>> +++ b/tools/perf/arch/arm64/util/header.c
>> @@ -0,0 +1,51 @@
>> +#include <fnmatch.h>
>> +#include <dirent.h>
>> +#include <unistd.h>
>> +#include <stdio.h>
>> +#include <stdlib.h>
>> +#include <string.h>
>> +#include <linux/stringify.h>
>> +#include "header.h"
>> +#include "util.h"
>> +
>> +#define LINUX_SYS_CPU_DIRECTORY "/sys/devices/system/cpu/"
>> +#define MIDR "/regs/identification/midr_el1"
>> +
>> +char *get_cpuid_str(void)
>> +{
>> + char *buf = malloc(128);
>> + FILE *file;
>> + char *ret = NULL;
>> + int cpu , nr_cpu;
>> + char sys_file[256];
>> +
>> + sprintf(sys_file, LINUX_SYS_CPU_DIRECTORY"kernel_max");
>> +
>> + file = fopen(sys_file, "r");
>> + if (!file)
>> + return ret;
>> +
>> + if (fscanf(file, "%d", &nr_cpu) != 1)
>> + return ret;
>> +
>> + /* kernel_max returns nr_cpu -1 */
>> + nr_cpu++;
>> +
>> + /*iterate till you read midr of first online cpu */
>> + for(cpu = 0; cpu < nr_cpu; cpu++)
>> + {
>> + sprintf(sys_file, LINUX_SYS_CPU_DIRECTORY"cpu%d"MIDR, cpu);
>> + file = fopen(sys_file, "r");
>> + if (file) {
>> + ret = fgets(buf, 128, file);
>> + if (ret) {
>> + buf[strlen(buf)-1] ='\0';
>> + fclose(file);
>> + return buf;
>> + }
>> + fclose(file);
>> + }
>> + }
>> + free(buf);
>> + return ret;
>> +}
>> --
>> 1.8.1.4
>>
thanks
Ganapat
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