From: K Prateek Nayak <kprateek.nayak@xxxxxxx>
Currently, there does not exist a straightforward way to extract the
names of the sched domains and match them to the per-cpu domain entry in
/proc/schedstat other than looking at the debugfs files which are only
visible after enabling "verbose" debug after commit 34320745dfc9
("sched/debug: Put sched/domains files under the verbose flag")
Since tools like `perf sched stats`[1] require displaying per-domain
information in user friendly manner, display the names of sched domain,
alongside their level in /proc/schedstat.
Domain names also makes the /proc/schedstat data unambiguous when some
of the cpus are offline. For example, on a 128 cpus AMD Zen3 machine
where CPU0 and CPU64 are SMT siblings and CPU64 is offline:
Before:
cpu0 ...
domain0 ...
domain1 ...
cpu1 ...
domain0 ...
domain1 ...
domain2 ...
After:
cpu0 ...
domain0 MC ...
domain1 PKG ...
cpu1 ...
domain0 SMT ...
domain1 MC ...
domain2 PKG ...
[1] https://lore.kernel.org/lkml/20241122084452.1064968-1-swapnil.sapkal@xxxxxxx/
Signed-off-by: K Prateek Nayak <kprateek.nayak@xxxxxxx>
Signed-off-by: Ravi Bangoria <ravi.bangoria@xxxxxxx>
Signed-off-by: Swapnil Sapkal <swapnil.sapkal@xxxxxxx>
Tested-by: James Clark <james.clark@xxxxxxxxxx>
---
kernel/sched/stats.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/sched/stats.c b/kernel/sched/stats.c
index 802bd9398a2e..5f563965976c 100644
--- a/kernel/sched/stats.c
+++ b/kernel/sched/stats.c
@@ -138,7 +138,7 @@ static int show_schedstat(struct seq_file *seq, void *v)
for_each_domain(cpu, sd) {
enum cpu_idle_type itype;
- seq_printf(seq, "domain%d %*pb", dcount++,
+ seq_printf(seq, "domain%d %s %*pb", dcount++, sd->name,
cpumask_pr_args(sched_domain_span(sd)));
for (itype = 0; itype < CPU_MAX_IDLE_TYPES; itype++) {
seq_printf(seq, " %u %u %u %u %u %u %u %u %u %u %u",
--
2.43.0
