| Message ID | 20200623123141.27747-3-liwei391@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | perf tools: Fix record failure when mixed with ARM SPE event | expand |
Hi Li, On Tue, Jun 23, 2020 at 08:31:41PM +0800, Wei Li wrote: > When recording with cache-misses and arm_spe_x event, i found that > it will just fail without showing any error info if i put cache-misses > after arm_spe_x event. > > [root@localhost 0620]# perf record -e cache-misses -e \ > arm_spe_0/ts_enable=1,pct_enable=1,pa_enable=1,load_filter=1,\ > jitter=1,store_filter=1,min_latency=0/ sleep 1 > [ perf record: Woken up 1 times to write data ] > [ perf record: Captured and wrote 0.067 MB perf.data ] > [root@localhost 0620]# perf record -e \ > arm_spe_0/ts_enable=1,pct_enable=1,pa_enable=1,load_filter=1,jitter=1,\ > store_filter=1,min_latency=0/ -e cache-misses sleep 1 > [root@localhost 0620]# > > Finally, i found the reason is that the parameter 'arm_spe_pmu' passed to > arm_spe_recording_init() in auxtrace_record__init() is wrong. When the > arm_spe_x event is not the last event, 'arm_spe_pmus[i]' will be out of > bounds. Yes, this indeed broken. The current code can only work if the only event to be traced is an arm_spe_X, or if it is the last event to be specified. Otherwise the last event type will be checked against all the arm_spe_pmus[i]->types, none will match and an out of bound i index will be used in arm_spc_recording_init(). Since this problem is not easy to figure out please include the above explanation in the changelog. > > It seems that the code can't support concurrent multiple different > arm_spe_x events currently. So add the code to check and record the > found 'arm_spe_pmu' to fix this issue. > > In fact, we don't support concurrent multiple same arm_spe_x events either, > that is checked in arm_spe_recording_options(), and it will show the > relevant info. > > Fixes: ffd3d18c20b8d ("perf tools: Add ARM Statistical Profiling Extensions (SPE) support") > Signed-off-by: Wei Li <liwei391@huawei.com> > --- > tools/perf/arch/arm/util/auxtrace.c | 10 +++++++++- > 1 file changed, 9 insertions(+), 1 deletion(-) > > diff --git a/tools/perf/arch/arm/util/auxtrace.c b/tools/perf/arch/arm/util/auxtrace.c > index 62b7b03d691a..7bb6f29e766c 100644 > --- a/tools/perf/arch/arm/util/auxtrace.c > +++ b/tools/perf/arch/arm/util/auxtrace.c > @@ -58,6 +58,7 @@ struct auxtrace_record > bool found_etm = false; > bool found_spe = false; > static struct perf_pmu **arm_spe_pmus; > + static struct perf_pmu *arm_spe_pmu; As far as I can tell the "static" doesn't do anything. > static int nr_spes = 0; > int i = 0; > > @@ -77,6 +78,13 @@ struct auxtrace_record > > for (i = 0; i < nr_spes; i++) { > if (evsel->core.attr.type == arm_spe_pmus[i]->type) { > + if (found_spe && (arm_spe_pmu != arm_spe_pmus[i])) { > + pr_err("Concurrent multiple SPE operation not currently supported\n"); > + *err = -EOPNOTSUPP; > + return NULL; > + } Instead of the above, which as you rightly pointed out, is also done in arm_spe_recording_options() it might be best to just fix the "if (!nr_spes)" condition: if (!nr_spes || arm_spe_pmu) continue Furthermore, instead of having a new arm_spe_pmu variable you could simply make found_spe a struct perf_pmu. That would be one less variable to take care of. > + > + arm_spe_pmu = arm_spe_pmus[i]; > found_spe = true; Last but not least do you know where the memory allocated for array arm_spe_pmus is released? If you can't find it either then we have a memory leak and it would be nice to have that fixed. Regards Mathieu PS: Leo Yan has spent a fair amount of time in the SPE code - please CC him on your next revision. > break; > } > @@ -94,7 +102,7 @@ struct auxtrace_record > > #if defined(__aarch64__) > if (found_spe) > - return arm_spe_recording_init(err, arm_spe_pmus[i]); > + return arm_spe_recording_init(err, arm_spe_pmu); > #endif > > /* > -- > 2.17.1 >
Hi Mathieu, On 2020/7/3 7:03, Mathieu Poirier wrote: > Hi Li, > > On Tue, Jun 23, 2020 at 08:31:41PM +0800, Wei Li wrote: >> When recording with cache-misses and arm_spe_x event, i found that >> it will just fail without showing any error info if i put cache-misses >> after arm_spe_x event. >> >> [root@localhost 0620]# perf record -e cache-misses -e \ >> arm_spe_0/ts_enable=1,pct_enable=1,pa_enable=1,load_filter=1,\ >> jitter=1,store_filter=1,min_latency=0/ sleep 1 >> [ perf record: Woken up 1 times to write data ] >> [ perf record: Captured and wrote 0.067 MB perf.data ] >> [root@localhost 0620]# perf record -e \ >> arm_spe_0/ts_enable=1,pct_enable=1,pa_enable=1,load_filter=1,jitter=1,\ >> store_filter=1,min_latency=0/ -e cache-misses sleep 1 >> [root@localhost 0620]# >> >> Finally, i found the reason is that the parameter 'arm_spe_pmu' passed to >> arm_spe_recording_init() in auxtrace_record__init() is wrong. When the >> arm_spe_x event is not the last event, 'arm_spe_pmus[i]' will be out of >> bounds. > > Yes, this indeed broken. > > The current code can only work if the only event to be > traced is an arm_spe_X, or if it is the last event to be specified. > Otherwise the last event type will be checked against all the > arm_spe_pmus[i]->types, none will match and an out of bound i index will be > used in arm_spc_recording_init(). > > Since this problem is not easy to figure out please include the above > explanation in the changelog. OK. >> >> It seems that the code can't support concurrent multiple different >> arm_spe_x events currently. So add the code to check and record the >> found 'arm_spe_pmu' to fix this issue. >> >> In fact, we don't support concurrent multiple same arm_spe_x events either, >> that is checked in arm_spe_recording_options(), and it will show the >> relevant info. >> >> Fixes: ffd3d18c20b8d ("perf tools: Add ARM Statistical Profiling Extensions (SPE) support") >> Signed-off-by: Wei Li <liwei391@huawei.com> >> --- >> tools/perf/arch/arm/util/auxtrace.c | 10 +++++++++- >> 1 file changed, 9 insertions(+), 1 deletion(-) >> >> diff --git a/tools/perf/arch/arm/util/auxtrace.c b/tools/perf/arch/arm/util/auxtrace.c >> index 62b7b03d691a..7bb6f29e766c 100644 >> --- a/tools/perf/arch/arm/util/auxtrace.c >> +++ b/tools/perf/arch/arm/util/auxtrace.c >> @@ -58,6 +58,7 @@ struct auxtrace_record >> bool found_etm = false; >> bool found_spe = false; >> static struct perf_pmu **arm_spe_pmus; >> + static struct perf_pmu *arm_spe_pmu; > > As far as I can tell the "static" doesn't do anything. > I will remove that in v2. >> static int nr_spes = 0; >> int i = 0; >> >> @@ -77,6 +78,13 @@ struct auxtrace_record >> >> for (i = 0; i < nr_spes; i++) { >> if (evsel->core.attr.type == arm_spe_pmus[i]->type) { >> + if (found_spe && (arm_spe_pmu != arm_spe_pmus[i])) { >> + pr_err("Concurrent multiple SPE operation not currently supported\n"); >> + *err = -EOPNOTSUPP; >> + return NULL; >> + } > > Instead of the above, which as you rightly pointed out, is also done in > arm_spe_recording_options() it might be best to just fix the "if (!nr_spes)" > condition: > if (!nr_spes || arm_spe_pmu) > continue This is more brief, i will use 'found_spe' as 'arm_spe_pmu' is not initialized. > Furthermore, instead of having a new arm_spe_pmu variable you could simply make > found_spe a struct perf_pmu. That would be one less variable to take care of. > >> + >> + arm_spe_pmu = arm_spe_pmus[i]; >> found_spe = true; > > Last but not least do you know where the memory allocated for array arm_spe_pmus > is released? If you can't find it either then we have a memory leak and it > would be nice to have that fixed. Yes, we have a memory leak here indeed, i forgot to free it in this function. As 'arm_spe_pmus' is defined as static, i think the author meant to assign it only at the first call, but this function is only called once when we executing 'record', should i go on fixing it or just drop the patch 1? > Regards > Mathieu > > PS: Leo Yan has spent a fair amount of time in the SPE code - please CC him on > your next revision. > Thanks, Wei
On Fri, Jul 03, 2020 at 12:06:15PM +0800, liwei (GF) wrote: [...] Thanks for Mathieu's looping and agreed with his comments. > > Last but not least do you know where the memory allocated for array arm_spe_pmus > > is released? If you can't find it either then we have a memory leak and it > > would be nice to have that fixed. > > Yes, we have a memory leak here indeed, i forgot to free it in this function. > As 'arm_spe_pmus' is defined as static, i think the author meant to assign it only at the first call, > but this function is only called once when we executing 'record', should i go on fixing it > or just drop the patch 1? I personally think patch 1 is reasonable. So for fixing memory leak, I did a quick check, it's good to release the array "arm_spe_pmus" in the function auxtrace_record__init(), since the array is only used in this function. Thanks, Leo
diff --git a/tools/perf/arch/arm/util/auxtrace.c b/tools/perf/arch/arm/util/auxtrace.c index 62b7b03d691a..7bb6f29e766c 100644 --- a/tools/perf/arch/arm/util/auxtrace.c +++ b/tools/perf/arch/arm/util/auxtrace.c @@ -58,6 +58,7 @@ struct auxtrace_record bool found_etm = false; bool found_spe = false; static struct perf_pmu **arm_spe_pmus; + static struct perf_pmu *arm_spe_pmu; static int nr_spes = 0; int i = 0; @@ -77,6 +78,13 @@ struct auxtrace_record for (i = 0; i < nr_spes; i++) { if (evsel->core.attr.type == arm_spe_pmus[i]->type) { + if (found_spe && (arm_spe_pmu != arm_spe_pmus[i])) { + pr_err("Concurrent multiple SPE operation not currently supported\n"); + *err = -EOPNOTSUPP; + return NULL; + } + + arm_spe_pmu = arm_spe_pmus[i]; found_spe = true; break; } @@ -94,7 +102,7 @@ struct auxtrace_record #if defined(__aarch64__) if (found_spe) - return arm_spe_recording_init(err, arm_spe_pmus[i]); + return arm_spe_recording_init(err, arm_spe_pmu); #endif /*
When recording with cache-misses and arm_spe_x event, i found that it will just fail without showing any error info if i put cache-misses after arm_spe_x event. [root@localhost 0620]# perf record -e cache-misses -e \ arm_spe_0/ts_enable=1,pct_enable=1,pa_enable=1,load_filter=1,\ jitter=1,store_filter=1,min_latency=0/ sleep 1 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.067 MB perf.data ] [root@localhost 0620]# perf record -e \ arm_spe_0/ts_enable=1,pct_enable=1,pa_enable=1,load_filter=1,jitter=1,\ store_filter=1,min_latency=0/ -e cache-misses sleep 1 [root@localhost 0620]# Finally, i found the reason is that the parameter 'arm_spe_pmu' passed to arm_spe_recording_init() in auxtrace_record__init() is wrong. When the arm_spe_x event is not the last event, 'arm_spe_pmus[i]' will be out of bounds. It seems that the code can't support concurrent multiple different arm_spe_x events currently. So add the code to check and record the found 'arm_spe_pmu' to fix this issue. In fact, we don't support concurrent multiple same arm_spe_x events either, that is checked in arm_spe_recording_options(), and it will show the relevant info. Fixes: ffd3d18c20b8d ("perf tools: Add ARM Statistical Profiling Extensions (SPE) support") Signed-off-by: Wei Li <liwei391@huawei.com> --- tools/perf/arch/arm/util/auxtrace.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-)