I am suspicious that this is a real issue, as this patch has been in
mainline for some time...
This simple change fixes the issue me:
diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index 91e6d9c..f4fd826 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -3576,7 +3576,7 @@ int perf_event__process_feature(struct perf_tool
*tool,
int max, err;
u16 type;
- if (!evsel->own_cpus)
+ if (!evsel->own_cpus || !(evsel->attr.read_format & PERF_FORMAT_ID)) //
roundabout check for !evsel->id
return 0;
ev = cpu_map_data__alloc(evsel->own_cpus, &size, &type, &max);
It turns out that evsel->id is NULL on a call to
perf_event__process_feature(), which upsets this code:
ev->header.type = PERF_RECORD_EVENT_UPDATE;
ev->header.size = (u16)size;
ev->type = PERF_EVENT_UPDATE__CPUS;
ev->id = evsel->id[0];
Please me let me know if a valid issue so we can get a fix in.
yea, I can see how we can get here with event having
its own CPUs, and we allocate the id array later at
the time we map the event
I wonder instead of skipping on this feature, we should
allocate the id array, like below
I did not test that.. need to find the server having event
with its own cpus.. also need to make sure evsel->cpus is
the way to go in here
Thanks for the fix, but I got this:
root@localhost:~# ./perf_debug_ record -e armv8_pmuv3_0/br_mis_pred/ sleep 1
Couldn't synthesize evsel cpus.
root@localhost:~#
thanks,
jirka
---
diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index 1ec1d9bc2d63..fb2a0dab3978 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -29,6 +29,7 @@
#include "symbol.h"
#include "debug.h"
#include "cpumap.h"
+#include "thread_map.h"
#include "pmu.h"
#include "vdso.h"
#include "strbuf.h"
@@ -3579,6 +3580,11 @@ perf_event__synthesize_event_update_cpus(struct
perf_tool *tool,
if (!evsel->own_cpus)
return 0;
+ if (!evsel->id ||
for my test, evsel->id is NULL
+ perf_evsel__alloc_id(evsel, cpu_map__nr(evsel->cpus),
+ thread_map__nr(evsel->threads)))
and then this function is not called as we return immediately. So did
you really want this:
if (!evsel->id && perf_evsel__alloc_id(...))
return -ENOMEM;
This looks to work:
root@localhost:~# ./perf_debug_ record -e armv8_pmuv3_0/br_mis_pred/ sleep 1
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.001 MB perf.data (7 samples) ]
root@localhost:~# ./perf_debug_ report
# To display the perf.data header info, please use
--header/--header-only option
#
#
# Total Lost Samples: 0
#
# Samples: 7 of event 'armv8_pmuv3_0/br_mis_pred/'
# Event count (approx.): 8260
#
# Overhead Command Shared Object Symbol
# ........ ....... ................. ......................
#
78.28% sleep libc-2.23.so [.] 0x00000000000faef0
20.53% sleep [kernel.kallsyms] [k] vmacache_find
1.09% sleep [kernel.kallsyms] [k] find_vma
0.10% perf_de [kernel.kallsyms] [k] perf_event_exec
#
# (Cannot load tips.txt file, please install perf!)
#
root@localhost:~#
+ return -ENOMEM;
+
ev = cpu_map_data__alloc(evsel->own_cpus, &size, &type, &max);
if (!ev)
return -ENOMEM;
.
Thanks,
John
