From 7297f47088274b0759dbef5d2c19d564d32521e6 Mon Sep 17 00:00:00 2001 From: Su Wang Date: Thu, 21 Mar 2019 00:14:14 -0400 Subject: perfmon: fix pmc hw indices out-dated when multiple pmc 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 --- src/plugins/perfmon/perfmon_periodic.c | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-) (limited to 'src/plugins/perfmon') diff --git a/src/plugins/perfmon/perfmon_periodic.c b/src/plugins/perfmon/perfmon_periodic.c index 12a1891518f..944a8e38e72 100644 --- a/src/plugins/perfmon/perfmon_periodic.c +++ b/src/plugins/perfmon/perfmon_periodic.c @@ -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; -- cgit 1.2.3-korg