| Message ID | 1491291403-29893-3-git-send-email-ganapatrao.kulkarni@cavium.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
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 >
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
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; +}
function get_cpuid_str returns midr_el1 value from first online cpu available. 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