Thread (23 messages) 23 messages, 6 authors, 2017-12-07

[PATCH v9 3/5] perf utils: use pmu->is_uncore to detect PMU UNCORE devices

From: Jin, Yao <hidden>
Date: 2017-12-05 02:12:19
Also in: lkml

Hi Kulkarni, Arnaldo,

This patch has been merged in perf/core branch today.

But I see a regression issue when I run the 'perf stat'.

With bisect checking, I locate to this patch.

commit ad8737a08973f5dca632bdd63cf2abc99670e540
Author: Ganapatrao Kulkarni [off-list ref]
Date:   Tue Oct 17 00:02:20 2017 +0530

     perf pmu: Use pmu->is_uncore to detect UNCORE devices

For example (on Intel skylake desktop),

1. The correct output should be (without this patch):

root at skl:/tmp# perf stat --per-thread -p 1754 -M CPI,IPC
^C
  Performance counter stats for process id '1754':

           vmstat-1754              1,882,798      inst_retired.any 
     #      0.8 CPI
           vmstat-1754              1,589,720      cycles
           vmstat-1754              1,882,798      inst_retired.any 
     #      1.2 IPC
           vmstat-1754              1,589,720      cpu_clk_unhalted.thread

        2.647443167 seconds time elapsed

2. With this patch, the output will be:

root at skl:/tmp# perf stat --per-thread -p 1754 -M CPI,IPC
^C
  Performance counter stats for process id '1754':

           vmstat-1754              1,945,589      inst_retired.any
           vmstat-1754        <not supported>      inst_retired.any
           vmstat-1754              1,609,892      cycles
           vmstat-1754              1,945,589      inst_retired.any
           vmstat-1754        <not supported>      inst_retired.any
           vmstat-1754              1,609,892      cpu_clk_unhalted.thread
           vmstat-1754        <not supported>      cpu_clk_unhalted.thread

        3.051274166 seconds time elapsed

Could you please help to take a look?

Thanks
Jin Yao

On 10/17/2017 2:32 AM, Ganapatrao Kulkarni wrote:
quoted hunk ↗ jump to hunk
PMU CORE devices are identified using sysfs filename cpu, however
on some platforms(like arm/arm64), PMU CORE sysfs name is not cpu.
Hence cpu cannot be used to differentiate PMU CORE/UNCORE devices.

commit:
  66ec1191 ("perf pmu: Unbreak perf record for arm/arm64 with events with explicit PMU")

has introduced pmu->is_uncore, which is set to PMU UNCORE devices only.
Adding changes to use pmu->is_uncore to identify UNCORE devices.

Acked-by: Will Deacon <redacted>
Tested-by: Shaokun Zhang <redacted>
Signed-off-by: Ganapatrao Kulkarni <redacted>
---
  tools/perf/util/pmu.c | 11 +++++++----
  1 file changed, 7 insertions(+), 4 deletions(-)
diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
index 8b17db5..9110718 100644
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -603,7 +603,6 @@ static void pmu_add_cpu_aliases(struct list_head *head, struct perf_pmu *pmu)
  	 */
  	i = 0;
  	while (1) {
-		const char *pname;
  
  		pe = &map->table[i++];
  		if (!pe->name) {
@@ -612,9 +611,13 @@ static void pmu_add_cpu_aliases(struct list_head *head, struct perf_pmu *pmu)
  			break;
  		}
  
-		pname = pe->pmu ? pe->pmu : "cpu";
-		if (strncmp(pname, name, strlen(pname)))
-			continue;
+		if (pmu->is_uncore) {
+			/* check for uncore devices */
+			if (pe->pmu == NULL)
+				continue;
+			if (strncmp(pe->pmu, name, strlen(pe->pmu)))
+				continue;
+		}
  
  		/* need type casts to override 'const' */
  		__perf_pmu__new_alias(head, NULL, (char *)pe->name,
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