Patch "tools/power turbostat: Increase the limit for fd opened" has been added to the 6.8-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    tools/power turbostat: Increase the limit for fd opened

to the 6.8-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     tools-power-turbostat-increase-the-limit-for-fd-open.patch
and it can be found in the queue-6.8 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 84f1e87bd3626da125ccb474d588f114ec27ae4c
Author: Wyes Karny <wyes.karny@xxxxxxx>
Date:   Tue Oct 3 05:07:51 2023 +0000

    tools/power turbostat: Increase the limit for fd opened
    
    [ 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@xxxxxxxxx>
    Tested-by: Doug Smythies <dsmythies@xxxxxxxxx>
    Signed-off-by: Wyes Karny <wyes.karny@xxxxxxx>
    Signed-off-by: Len Brown <len.brown@xxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/tools/power/x86/turbostat/turbostat.c b/tools/power/x86/turbostat/turbostat.c
index fca7913f6c84d..2550a0e35914f 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 };
@@ -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 @@ int main(int argc, char **argv)
 
 	probe_sysfs();
 
+	if (!getuid())
+		set_rlimit();
+
 	turbostat_init();
 
 	msr_sum_record();