Re: [PATCH v5 2/8] perf: Use perf_pmu__open_file() and perf_pmu__scan_file()

From: Arnaldo Carvalho de Melo
Date: Fri Jan 20 2023 - 12:22:10 EST

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In reply to: James Clark: "[PATCH v5 2/8] perf: Use perf_pmu__open_file() and perf_pmu__scan_file()"
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Em Fri, Jan 20, 2023 at 02:36:55PM +0000, James Clark escreveu:
> Remove some code that duplicates existing methods. Copy strings where
> const strings are required.
>
> No functional changes.

Have you used 'perf test'?

[acme@quaco perf]$ perf test -v python
Couldn't bump rlimit(MEMLOCK), failures may take place when creating BPF maps, etc
19: 'import perf' in python :
--- start ---
test child forked, pid 232379
python usage test: "echo "import sys ; sys.path.append('/tmp/build/perf/python'); import perf" | '/usr/bin/python3' "
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
ImportError: /tmp/build/perf/python/perf.cpython-310-x86_64-linux-gnu.so: undefined symbol: perf_pmu__scan_file
test child finished with -1
---- end ----
'import perf' in python: FAILED!
[acme@quaco perf]$

> Reviewed-by: Leo Yan <leo.yan@xxxxxxxxxx>
> Signed-off-by: James Clark <james.clark@xxxxxxx>
> ---
> tools/perf/util/cputopo.c | 9 +-------
> tools/perf/util/pmu-hybrid.c | 27 +++++-------------------
> tools/perf/util/pmu.c | 40 +++++++++++-------------------------
> tools/perf/util/pmu.h | 3 ++-
> 4 files changed, 20 insertions(+), 59 deletions(-)
>
> diff --git a/tools/perf/util/cputopo.c b/tools/perf/util/cputopo.c
> index 1a3ff6449158..e08797c3cdbc 100644
> --- a/tools/perf/util/cputopo.c
> +++ b/tools/perf/util/cputopo.c
> @@ -422,8 +422,6 @@ void numa_topology__delete(struct numa_topology *tp)
> static int load_hybrid_node(struct hybrid_topology_node *node,
> struct perf_pmu *pmu)
> {
> - const char *sysfs;
> - char path[PATH_MAX];
> char *buf = NULL, *p;
> FILE *fp;
> size_t len = 0;
> @@ -432,12 +430,7 @@ static int load_hybrid_node(struct hybrid_topology_node *node,
> if (!node->pmu_name)
> return -1;
>
> - sysfs = sysfs__mountpoint();
> - if (!sysfs)
> - goto err;
> -
> - snprintf(path, PATH_MAX, CPUS_TEMPLATE_CPU, sysfs, pmu->name);
> - fp = fopen(path, "r");
> + fp = perf_pmu__open_file(pmu, "cpus");
> if (!fp)
> goto err;
>
> diff --git a/tools/perf/util/pmu-hybrid.c b/tools/perf/util/pmu-hybrid.c
> index f51ccaac60ee..38628805a952 100644
> --- a/tools/perf/util/pmu-hybrid.c
> +++ b/tools/perf/util/pmu-hybrid.c
> @@ -20,32 +20,15 @@ LIST_HEAD(perf_pmu__hybrid_pmus);
>
> bool perf_pmu__hybrid_mounted(const char *name)
> {
> - char path[PATH_MAX];
> - const char *sysfs;
> - FILE *file;
> - int n, cpu;
> + int cpu;
> + char pmu_name[PATH_MAX];
> + struct perf_pmu pmu = {.name = pmu_name};
>
> if (strncmp(name, "cpu_", 4))
> return false;
>
> - sysfs = sysfs__mountpoint();
> - if (!sysfs)
> - return false;
> -
> - snprintf(path, PATH_MAX, CPUS_TEMPLATE_CPU, sysfs, name);
> - if (!file_available(path))
> - return false;
> -
> - file = fopen(path, "r");
> - if (!file)
> - return false;
> -
> - n = fscanf(file, "%u", &cpu);
> - fclose(file);
> - if (n <= 0)
> - return false;
> -
> - return true;
> + strlcpy(pmu_name, name, sizeof(pmu_name));
> + return perf_pmu__scan_file(&pmu, "cpus", "%u", &cpu) > 0;
> }
>
> struct perf_pmu *perf_pmu__find_hybrid_pmu(const char *name)
> diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
> index 1edbb714ff32..a771a5972fc5 100644
> --- a/tools/perf/util/pmu.c
> +++ b/tools/perf/util/pmu.c
> @@ -571,45 +571,31 @@ static void pmu_read_sysfs(void)
> closedir(dir);
> }
>
> -static struct perf_cpu_map *__pmu_cpumask(const char *path)
> -{
> - FILE *file;
> - struct perf_cpu_map *cpus;
> -
> - file = fopen(path, "r");
> - if (!file)
> - return NULL;
> -
> - cpus = perf_cpu_map__read(file);
> - fclose(file);
> - return cpus;
> -}
> -
> /*
> * Uncore PMUs have a "cpumask" file under sysfs. CPU PMUs (e.g. on arm/arm64)
> * may have a "cpus" file.
> */
> #define SYS_TEMPLATE_ID "./bus/event_source/devices/%s/identifier"
> -#define CPUS_TEMPLATE_UNCORE "%s/bus/event_source/devices/%s/cpumask"
>
> static struct perf_cpu_map *pmu_cpumask(const char *name)
> {
> - char path[PATH_MAX];
> struct perf_cpu_map *cpus;
> - const char *sysfs = sysfs__mountpoint();
> const char *templates[] = {
> - CPUS_TEMPLATE_UNCORE,
> - CPUS_TEMPLATE_CPU,
> + "cpumask",
> + "cpus",
> NULL
> };
> const char **template;
> + char pmu_name[PATH_MAX];
> + struct perf_pmu pmu = {.name = pmu_name};
> + FILE *file;
>
> - if (!sysfs)
> - return NULL;
> -
> + strlcpy(pmu_name, name, sizeof(pmu_name));
> for (template = templates; *template; template++) {
> - snprintf(path, PATH_MAX, *template, sysfs, name);
> - cpus = __pmu_cpumask(path);
> + file = perf_pmu__open_file(&pmu, *template);
> + if (!file)
> + continue;
> + cpus = perf_cpu_map__read(file);
> if (cpus)
> return cpus;
> }
> @@ -620,13 +606,11 @@ static struct perf_cpu_map *pmu_cpumask(const char *name)
> static bool pmu_is_uncore(const char *name)
> {
> char path[PATH_MAX];
> - const char *sysfs;
>
> if (perf_pmu__hybrid_mounted(name))
> return false;
>
> - sysfs = sysfs__mountpoint();
> - snprintf(path, PATH_MAX, CPUS_TEMPLATE_UNCORE, sysfs, name);
> + perf_pmu__pathname_scnprintf(path, sizeof(path), name, "cpumask");
> return file_available(path);
> }
>
> @@ -1737,7 +1721,7 @@ bool pmu_have_event(const char *pname, const char *name)
> return false;
> }
>
> -static FILE *perf_pmu__open_file(struct perf_pmu *pmu, const char *name)
> +FILE *perf_pmu__open_file(struct perf_pmu *pmu, const char *name)
> {
> char path[PATH_MAX];
>
> diff --git a/tools/perf/util/pmu.h b/tools/perf/util/pmu.h
> index 96d030c8b3b3..742d4db319a0 100644
> --- a/tools/perf/util/pmu.h
> +++ b/tools/perf/util/pmu.h
> @@ -7,6 +7,7 @@
> #include <linux/perf_event.h>
> #include <linux/list.h>
> #include <stdbool.h>
> +#include <stdio.h>
> #include "parse-events.h"
> #include "pmu-events/pmu-events.h"
>
> @@ -22,7 +23,6 @@ enum {
> };
>
> #define PERF_PMU_FORMAT_BITS 64
> -#define CPUS_TEMPLATE_CPU "%s/bus/event_source/devices/%s/cpus"
> #define MAX_PMU_NAME_LEN 128
>
> struct perf_event_attr;
> @@ -262,5 +262,6 @@ double perf_pmu__cpu_slots_per_cycle(void);
> int perf_pmu__event_source_devices_scnprintf(char *pathname, size_t size);
> int perf_pmu__pathname_scnprintf(char *buf, size_t size,
> const char *pmu_name, const char *filename);
> +FILE *perf_pmu__open_file(struct perf_pmu *pmu, const char *name);
>
> #endif /* __PMU_H */
> --
> 2.25.1
>

--

- Arnaldo

Next message: Konrad Dybcio: "[PATCH v2 1/5] drm/msm/a6xx: Add support for A640 speed binning"
Previous message: Paul E. McKenney: "Re: [PATCH 39/41] kernel/fork: throttle call_rcu() calls in vm_area_free"
In reply to: James Clark: "[PATCH v5 2/8] perf: Use perf_pmu__open_file() and perf_pmu__scan_file()"
Next in thread: Arnaldo Carvalho de Melo: "Re: [PATCH v5 2/8] perf: Use perf_pmu__open_file() and perf_pmu__scan_file()"
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