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perfmon: fix pmc hw indices out-dated when multiple pmc

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When adding two or more events using a single "set pmc",
the pmc hardware indices might be out-dated due to kernel
reschdeduling the perf_event hardware counters.
E.g. set pmc cpu-cycles cache-misses

Solution:
Open and enable all the events first, then aquire the
indices from the kernel.

Change-Id: I6913a871ab169e3b2855ac6159f527a1fca343e9
Signed-off-by: Su Wang <su.z.wang@ericsson.com>
This commit is contained in:
Su Wang
2019-03-21 00:14:14 -04:00
committed by Damjan Marion
parent cb36a1dbaf
commit 7297f47088
1 changed files with 15 additions and 3 deletions
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18
src/plugins/perfmon/perfmon_periodic.c
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@@ -171,19 +171,31 @@ enable_current_events (perfmon_main_t * pm)
if (ioctl (fd, PERF_EVENT_IOC_ENABLE, 0) < 0)
clib_unix_warning ("enable ioctl");
pm->perf_event_pages[i][my_thread_index] = (void *) p;
pm->pm_fds[i][my_thread_index] = fd;
}
/*
* Hardware events must be all opened and enabled before aquiring
* pmc indices, otherwise the pmc indices might be out-dated.
*/
for (i = 0; i < limit; i++)
{
p =
(struct perf_event_mmap_page *)
pm->perf_event_pages[i][my_thread_index];
/*
* Software event counters - and others not capable of being
* read via the "rdpmc" instruction - will be read
* by system calls.
*/
if (pe.type == PERF_TYPE_SOFTWARE || p->cap_user_rdpmc == 0)
if (p == 0 || p->cap_user_rdpmc == 0)
index = ~0;
else
index = p->index - 1;
pm->rdpmc_indices[i][my_thread_index] = index;
pm->perf_event_pages[i][my_thread_index] = (void *) p;
pm->pm_fds[i][my_thread_index] = fd;
}
pm->n_active = i;