Em Thu, Sep 10, 2015 at 10:58:38AM -0300, Arnaldo Carvalho de Melo escreveu:
> Em Tue, Sep 08, 2015 at 03:32:44PM -0400, kan.li...@intel.com escreveu:
> > This patch introduces generic FEAT for CPU attributes. For the patch
> > set, we only need cpu max frequency. But it can be easily extented to
> > support more other CPU attributes.
> > The cpu max frequency is from the first online cpu.
> Ok, but don't we have to do error handling? i.e. you are returning 0 for
> any error in trying to read the cpu max freq, shouldn't we bail out
> somewhere?
> And please move this get_cpu_max_freq() thing out of the cpumap.[ch]
> files, it is not even a need completely specific to perf tooling, there
> must be somewhere in tools/lib/api/ (kernel APIs) where this fits, no?
So, I've updated my perf/env branch with routines to do that, that uses
infrastructure to read files from virtual dirs that was there plus a few
I just introduced, in the same vein, I will update your patches to use
them and put there as well, for your consideration.
The HEAD there is the one below:
- Arnaldo
commit 2bc1fae4ed8a842f52dc374449d37c3ec1fa1986
Author: Arnaldo Carvalho de Melo <a...@redhat.com>
Date: Thu Sep 10 12:20:14 2015 -0300
tools lib cpu: Introduce cpu.[ch] to read sysfs cpu related information
E.g.:
$ ./cpu__get_max_freq
3200000
It does that, as Kan's patch does, by looking at these files:
$ cat /sys/devices/system/cpu/online
0-3
$ ./sysfs__read_ull
devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq
/sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq=3200000
$
I.e. find out the first online CPU, then read its cpufreq info.
But do it in tools/lib/api/, so that other tools living code can use
it, not just perf.
Based-on-a-patch-by: Kan Liang <kan.li...@intel.com>
Cc: Adrian Hunter <adrian.hun...@intel.com>
Cc: Borislav Petkov <b...@suse.de>
Cc: David Ahern <dsah...@gmail.com>
Cc: Frederic Weisbecker <fweis...@gmail.com>
Cc: Jiri Olsa <jo...@redhat.com>
Cc: Namhyung Kim <namhy...@kernel.org>
Cc: Stephane Eranian <eran...@google.com>
Link: http://lkml.kernel.org/n/tip-915v4cvxqplaub8qco66b...@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <a...@redhat.com>
diff --git a/tools/lib/api/Build b/tools/lib/api/Build
index 3653965cf481..e8b8a23b9bf4 100644
--- a/tools/lib/api/Build
+++ b/tools/lib/api/Build
@@ -1,2 +1,3 @@
libapi-y += fd/
libapi-y += fs/
+libapi-y += cpu.o
diff --git a/tools/lib/api/cpu.c b/tools/lib/api/cpu.c
new file mode 100644
index 000000000000..8c6489356e3a
--- /dev/null
+++ b/tools/lib/api/cpu.c
@@ -0,0 +1,18 @@
+#include <stdio.h>
+
+#include "cpu.h"
+#include "fs/fs.h"
+
+int cpu__get_max_freq(unsigned long long *freq)
+{
+ char entry[PATH_MAX];
+ int cpu;
+
+ if (sysfs__read_int("devices/system/cpu/online", &cpu) < 0)
+ return -1;
+
+ snprintf(entry, sizeof(entry),
+ "devices/system/cpu/cpu%d/cpufreq/cpuinfo_max_freq", cpu);
+
+ return sysfs__read_ull(entry, freq);
+}
diff --git a/tools/lib/api/cpu.h b/tools/lib/api/cpu.h
new file mode 100644
index 000000000000..81e9d3955961
--- /dev/null
+++ b/tools/lib/api/cpu.h
@@ -0,0 +1,6 @@
+#ifndef __API_CPU__
+#define __API_CPU__
+
+int cpu__get_max_freq(unsigned long long *freq);
+
+#endif /* __API_CPU__ */
--
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