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Date: Fri, 30 May 2014 12:28:30 -0300
From: Arnaldo Carvalho de Melo <acme@...nel.org>
To: Don Zickus <dzickus@...hat.com>
Cc: jolsa@...hat.com, Peter Zijlstra <peterz@...radead.org>,
LKML <linux-kernel@...r.kernel.org>, namhyung@...il.com,
eranian@...gle.com, Andi Kleen <andi@...stfloor.org>
Subject: Re: [PATCH 6/7 V2] perf: Add support to dynamically get cacheline
size
Em Fri, May 30, 2014 at 10:50:25AM -0400, Don Zickus escreveu:
> Different arches may have different cacheline sizes. Look it up and set
> a global variable for reference.
[acme@zoo linux]$ strings `which getconf` | grep LINESIZE
LEVEL1_ICACHE_LINESIZE
LEVEL1_DCACHE_LINESIZE
LEVEL2_CACHE_LINESIZE
LEVEL3_CACHE_LINESIZE
LEVEL4_CACHE_LINESIZE
[acme@zoo linux]$
man sysconf
That is what I use in pahole, for instance:
[acme@zoo pahole]$ grep sysconf *.c
dwarves_fprintf.c: long sys_cacheline_size =
sysconf(_SC_LEVEL1_DCACHE_LINESIZE);
[acme@zoo pahole]$
- Arnaldo
> Signed-off-by: Don Zickus <dzickus@...hat.com>
>
> ---
> V3: remove unneeded cpumap.h (Namhyung Kim)
> V2: change to be global and setup in perf.c
> use filename__read_int for setup
> ---
> tools/perf/perf.c | 5 +++++
> tools/perf/util/cpumap.c | 27 +++++++++++++++++++++++++++
> tools/perf/util/cpumap.h | 3 +++
> tools/perf/util/util.c | 1 +
> tools/perf/util/util.h | 1 +
> 5 files changed, 37 insertions(+)
>
> diff --git a/tools/perf/perf.c b/tools/perf/perf.c
> index 431798a..dabf08b 100644
> --- a/tools/perf/perf.c
> +++ b/tools/perf/perf.c
> @@ -13,6 +13,7 @@
> #include "util/quote.h"
> #include "util/run-command.h"
> #include "util/parse-events.h"
> +#include "util/cpumap.h"
> #include <api/fs/debugfs.h>
> #include <pthread.h>
>
> @@ -459,6 +460,10 @@ int main(int argc, const char **argv)
> /* The page_size is placed in util object. */
> page_size = sysconf(_SC_PAGE_SIZE);
>
> + /* The cacheline_size is placed in util objet */
> + if (cpu__setup_cacheline_size() < 0)
> + goto out;
> +
> cmd = perf_extract_argv0_path(argv[0]);
> if (!cmd)
> cmd = "perf-help";
> diff --git a/tools/perf/util/cpumap.c b/tools/perf/util/cpumap.c
> index c4e55b7..1029982 100644
> --- a/tools/perf/util/cpumap.c
> +++ b/tools/perf/util/cpumap.c
> @@ -477,3 +477,30 @@ int cpu__setup_cpunode_map(void)
> closedir(dir1);
> return 0;
> }
> +
> +int cpu__setup_cacheline_size(void)
> +{
> + const char *mnt;
> + char path[PATH_MAX];
> + int n, size;
> +
> +
> + mnt = sysfs__mountpoint();
> + if (!mnt)
> + return -1;
> +
> + n = snprintf(path, PATH_MAX, "%s/devices/system/cpu/cpu0/cache/index0/coherency_line_size", mnt);
> + if (n == PATH_MAX) {
> + pr_err("sysfs path crossed PATH_MAX(%d) size\n", PATH_MAX);
> + return -1;
> + }
> +
> + if (filename__read_int(path, &size)) {
> + pr_err("Can not read cacheline size\n");
> + return -1;
> + }
> +
> + cacheline_size = size;
> +
> + return 0;
> +}
> diff --git a/tools/perf/util/cpumap.h b/tools/perf/util/cpumap.h
> index 61a6548..507d7fd 100644
> --- a/tools/perf/util/cpumap.h
> +++ b/tools/perf/util/cpumap.h
> @@ -5,6 +5,7 @@
> #include <stdbool.h>
>
> #include "perf.h"
> +#include "util/util.h"
> #include "util/debug.h"
>
> struct cpu_map {
> @@ -81,4 +82,6 @@ static inline int cpu__get_node(int cpu)
> return cpunode_map[cpu];
> }
>
> +int cpu__setup_cacheline_size(void);
> +
> #endif /* __PERF_CPUMAP_H */
> diff --git a/tools/perf/util/util.c b/tools/perf/util/util.c
> index 7fff6be..95aefa7 100644
> --- a/tools/perf/util/util.c
> +++ b/tools/perf/util/util.c
> @@ -17,6 +17,7 @@
> * XXX We need to find a better place for these things...
> */
> unsigned int page_size;
> +int cacheline_size;
>
> bool test_attr__enabled;
>
> diff --git a/tools/perf/util/util.h b/tools/perf/util/util.h
> index b03da44..6686436 100644
> --- a/tools/perf/util/util.h
> +++ b/tools/perf/util/util.h
> @@ -304,6 +304,7 @@ char *rtrim(char *s);
> void dump_stack(void);
>
> extern unsigned int page_size;
> +extern int cacheline_size;
>
> void get_term_dimensions(struct winsize *ws);
>
> --
> 1.7.11.7
--
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