On 3/27/20 12:06 PM, Kajol Jain wrote:
Commit 2b206ee6b0df ("powerpc/perf/hv-24x7: Display change in counter
values")' added to print _change_ in the counter value rather then raw
value for 24x7 counters. Incase of transactions, the event count
is set to 0 at the beginning of the transaction. It also sets
the event's prev_count to the raw value at the time of initialization.
Because of setting event count to 0, we are seeing some weird behaviour,
whenever we run multiple 24x7 events at a time.
For example:
command#: ./perf stat -e "{hv_24x7/PM_MCS01_128B_RD_DISP_PORT01,chip=0/,
hv_24x7/PM_MCS01_128B_RD_DISP_PORT01,chip=1/}"
-C 0 -I 1000 sleep 100
1.000121704 120
hv_24x7/PM_MCS01_128B_RD_DISP_PORT01,chip=0/
1.000121704 5
hv_24x7/PM_MCS01_128B_RD_DISP_PORT01,chip=1/
2.000357733 8
hv_24x7/PM_MCS01_128B_RD_DISP_PORT01,chip=0/
2.000357733 10
hv_24x7/PM_MCS01_128B_RD_DISP_PORT01,chip=1/
3.000495215 18,446,744,073,709,551,616
hv_24x7/PM_MCS01_128B_RD_DISP_PORT01,chip=0/
3.000495215 18,446,744,073,709,551,616
hv_24x7/PM_MCS01_128B_RD_DISP_PORT01,chip=1/
4.000641884 56
hv_24x7/PM_MCS01_128B_RD_DISP_PORT01,chip=0/
4.000641884 18,446,744,073,709,551,616
hv_24x7/PM_MCS01_128B_RD_DISP_PORT01,chip=1/
5.000791887 18,446,744,073,709,551,616
hv_24x7/PM_MCS01_128B_RD_DISP_PORT01,chip=0/
Getting these large values in case we do -I.
As we are setting event_count to 0, for interval case, overall event_count is
not
coming in incremental order. As we may can get new delta lesser then previous
count.
Because of which when we print intervals, we are getting negative value which
create
these large values.
This patch removes part where we set event_count to 0 in function
'h_24x7_event_read'. There won't be much impact as we do set
event->hw.prev_count
to the raw value at the time of initialization to print change value.
With this patch
In power9 platform
command#: ./perf stat -e "{hv_24x7/PM_MCS01_128B_RD_DISP_PORT01,chip=0/,
hv_24x7/PM_MCS01_128B_RD_DISP_PORT01,chip=1/}"
-C 0 -I 1000 sleep 100
1.000117685 93
hv_24x7/PM_MCS01_128B_RD_DISP_PORT01,chip=0/
1.000117685 1
hv_24x7/PM_MCS01_128B_RD_DISP_PORT01,chip=1/
2.000349331 98
hv_24x7/PM_MCS01_128B_RD_DISP_PORT01,chip=0/
2.000349331 2
hv_24x7/PM_MCS01_128B_RD_DISP_PORT01,chip=1/
3.000495900 131
hv_24x7/PM_MCS01_128B_RD_DISP_PORT01,chip=0/
3.000495900 4
hv_24x7/PM_MCS01_128B_RD_DISP_PORT01,chip=1/
4.000645920 204
hv_24x7/PM_MCS01_128B_RD_DISP_PORT01,chip=0/
4.000645920 61
hv_24x7/PM_MCS01_128B_RD_DISP_PORT01,chip=1/
4.284169997 22
hv_24x7/PM_MCS01_128B_RD_DISP_PORT01,chip=0/
Signed-off-by: Kajol Jain <[email protected]>
Suggested-by: Sukadev Bhattiprolu <[email protected]>
Tested-by: Madhavan Srinivasan <[email protected]>
---
arch/powerpc/perf/hv-24x7.c | 10 ----------
1 file changed, 10 deletions(-)
diff --git a/arch/powerpc/perf/hv-24x7.c b/arch/powerpc/perf/hv-24x7.c
index 573e0b309c0c..48e8f4b17b91 100644
--- a/arch/powerpc/perf/hv-24x7.c
+++ b/arch/powerpc/perf/hv-24x7.c
@@ -1400,16 +1400,6 @@ static void h_24x7_event_read(struct perf_event *event)
h24x7hw = &get_cpu_var(hv_24x7_hw);
h24x7hw->events[i] = event;
put_cpu_var(h24x7hw);
- /*
- * Clear the event count so we can compute the _change_
- * in the 24x7 raw counter value at the end of the txn.
- *
- * Note that we could alternatively read the 24x7 value
- * now and save its value in event->hw.prev_count. But
- * that would require issuing a hcall, which would then
- * defeat the purpose of using the txn interface.
- */
- local64_set(&event->count, 0);
}
put_cpu_var(hv_24x7_reqb);
