tools/power turbostat: Increase the limit for fd opened

When running turbostat, a system with 512 cpus reaches the limit for
maximum number of file descriptors that can be opened. To solve this
problem, the limit is raised to 2^15, which is a large enough number.

Below data is collected from AMD server systems while running turbostat:

|-----------+-------------------------------|
| # of cpus | # of opened fds for turbostat |
|-----------+-------------------------------|
| 128       | 260                           |
|-----------+-------------------------------|
| 192       | 388                           |
|-----------+-------------------------------|
| 512       | 1028                          |
|-----------+-------------------------------|

So, the new max limit would be sufficient up to 2^14 cpus (but this
also depends on how many counters are enabled).

Reviewed-by: Doug Smythies <dsmythies@telus.net>
Tested-by: Doug Smythies <dsmythies@telus.net>
Signed-off-by: Wyes Karny <wyes.karny@amd.com>
Signed-off-by: Len Brown <len.brown@intel.com>

diff --git a/tools/power/x86/turbostat/turbostat.c b/tools/power/x86/turbostat/turbostat.c
index fca7913f6c84de91fe32f3216a6d5f96441b8fd5..2550a0e35914faa56697055a40f15fc94d8f0b05 100644 (file)
--- a/tools/power/x86/turbostat/turbostat.c
+++ b/tools/power/x86/turbostat/turbostat.c
@@ -53,6 +53,8 @@
 #define        NAME_BYTES 20
 #define PATH_BYTES 128
 
+#define MAX_NOFILE 0x8000
+
 enum counter_scope { SCOPE_CPU, SCOPE_CORE, SCOPE_PACKAGE };
 enum counter_type { COUNTER_ITEMS, COUNTER_CYCLES, COUNTER_SECONDS, COUNTER_USEC };
 enum counter_format { FORMAT_RAW, FORMAT_DELTA, FORMAT_PERCENT };
@@ -6705,6 +6707,22 @@ void cmdline(int argc, char **argv)
        }
 }
 
+void set_rlimit(void)
+{
+       struct rlimit limit;
+
+       if (getrlimit(RLIMIT_NOFILE, &limit) < 0)
+               err(1, "Failed to get rlimit");
+
+       if (limit.rlim_max < MAX_NOFILE)
+               limit.rlim_max = MAX_NOFILE;
+       if (limit.rlim_cur < MAX_NOFILE)
+               limit.rlim_cur = MAX_NOFILE;
+
+       if (setrlimit(RLIMIT_NOFILE, &limit) < 0)
+               err(1, "Failed to set rlimit");
+}
+
 int main(int argc, char **argv)
 {
        int fd, ret;
@@ -6730,6 +6748,9 @@ skip_cgroup_setting:
 
        probe_sysfs();
 
+       if (!getuid())
+               set_rlimit();
+
        turbostat_init();
 
        msr_sum_record();