[PATCH AUTOSEL 6.6 02/29] tools/power turbostat: Increase the limit for fd opened

Sasha Levin
2024-04-22T23:56:14Z

From: Wyes Karny <wyes.karny@amd.com>

[ Upstream commit 3ac1d14d0583a2de75d49a5234d767e2590384dd ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
tools/power/x86/turbostat/turbostat.c | 21 +++++++++++++++++++++
1 file changed, 21 insertions(+)

diff --git a/tools/power/x86/turbostat/turbostat.c b/tools/power/x86/turbostat/turbostat.c
index 9602a4798f383..5b892c53fc2c2 100644
--- 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 };
@@ -6719,6 +6721,22 @@ 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)
{
outf = stderr;
@@ -6731,6 +6749,9 @@ int main(int argc, char **argv)

probe_sysfs();

+ if (!getuid())
+ set_rlimit();
+
turbostat_init();

msr_sum_record();
--
2.43.0