On 6/20/2019 8:50 AM, Peter Zijlstra wrote:
On Mon, Jun 17, 2019 at 09:41:37PM +0800, Zhang Rui wrote:
After S3 suspend/resume, "perf stat -I 1000 -e power/energy-pkg/ -a"
reports an insane value for the very first sampling period after resume
as shown below.
19.278989977 2.16 Joules power/energy-pkg/
20.279373569 1.96 Joules power/energy-pkg/
21.279765481 2.09 Joules power/energy-pkg/
22.280305420 2.10 Joules power/energy-pkg/
25.504782277 4,294,966,686.01 Joules power/energy-pkg/
26.505114993 3.58 Joules power/energy-pkg/
27.505471758 1.66 Joules power/energy-pkg/
Fix this by resetting the counter right after resume.
Cute...
+#ifdef CONFIG_PM
+
+static int perf_rapl_suspend(void)
+{
+ int i;
+
+ get_online_cpus();
+ for (i = 0; i < rapl_pmus->maxpkg; i++)
+ rapl_pmu_update_all(rapl_pmus->pmus[i]);
+ put_online_cpus();
+ return 0;
+}
+
+static void perf_rapl_resume(void)
+{
+ int i;
+
+ get_online_cpus();
+ for (i = 0; i < rapl_pmus->maxpkg; i++)
+ rapl_pmu_restart_all(rapl_pmus->pmus[i]);
+ put_online_cpus();
+}
What's the reason for that get/put_online_cpus() here ?
It looks like syscore_* functions are executed with one CPU on-line.
If so, they may not be the right place for the rapl callback.
Rapl is per socket. The driver manipulates the registers on the first
CPU of each socket. I think we need to update/restart the counters on
all sockets. That's the reason I add get/put_online_cpus() in the
original patch.
Besides, I think we also need to call rapl_pmu_restart/update_all() on
the target cpu.
Thanks,
Kan
