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From: Jiri Olsa <jolsa@redhat.com>
To: Leo Yan <leo.yan@linaro.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	Mark Rutland <mark.rutland@arm.com>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Namhyung Kim <namhyung@kernel.org>,
	Adrian Hunter <adrian.hunter@intel.com>,
	Andi Kleen <ak@linux.intel.com>, Ian Rogers <irogers@google.com>,
	Nick Desaulniers <ndesaulniers@google.com>,
	"Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>,
	Kemeng Shi <shikemeng@huawei.com>,
	James Clark <james.clark@arm.com>, Wei Li <liwei391@huawei.com>,
	Al Grant <Al.Grant@arm.com>, Will Deacon <will@kernel.org>,
	Mathieu Poirier <mathieu.poirier@linaro.org>,
	Mike Leach <mike.leach@linaro.org>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 02/14] perf mem: Introduce weak function perf_mem_events__ptr()
Date: Fri, 4 Sep 2020 17:52:51 +0200	[thread overview]
Message-ID: <20200904155251.GC939481@krava> (raw)
In-Reply-To: <20200904003447.GB5979@leoy-ThinkPad-X240s>

On Fri, Sep 04, 2020 at 08:34:47AM +0800, Leo Yan wrote:
> Hi Jiri,
> 
> On Thu, Sep 03, 2020 at 03:50:54PM +0200, Jiri Olsa wrote:
> > On Tue, Sep 01, 2020 at 09:38:03AM +0100, Leo Yan wrote:
> > 
> > SNIP
> > 
> > > @@ -2941,30 +2942,38 @@ static int perf_c2c__record(int argc, const char **argv)
> > >  	rec_argv[i++] = "record";
> > >  
> > >  	if (!event_set) {
> > > -		perf_mem_events[PERF_MEM_EVENTS__LOAD].record  = true;
> > > -		perf_mem_events[PERF_MEM_EVENTS__STORE].record = true;
> > > +		e = perf_mem_events__ptr(PERF_MEM_EVENTS__LOAD);
> > > +		e->record = true;
> > > +
> > > +		e = perf_mem_events__ptr(PERF_MEM_EVENTS__STORE);
> > > +		e->record = true;
> > >  	}
> > >  
> > > -	if (perf_mem_events[PERF_MEM_EVENTS__LOAD].record)
> > > +	e = perf_mem_events__ptr(PERF_MEM_EVENTS__LOAD);
> > > +	if (e->record)
> > >  		rec_argv[i++] = "-W";
> > >  
> > >  	rec_argv[i++] = "-d";
> > >  	rec_argv[i++] = "--phys-data";
> > >  	rec_argv[i++] = "--sample-cpu";
> > >  
> > > -	for (j = 0; j < PERF_MEM_EVENTS__MAX; j++) {
> > > -		if (!perf_mem_events[j].record)
> > > +	j = 0;
> > > +	while ((e = perf_mem_events__ptr(j)) != NULL) {
> > > +		if (!e->record) {
> > 
> > you could keep the above 'for loop' in here, it seems better
> > than taking care of j++
> 
> Actually in patch v1 I did this way :)  I followed James' suggestion to
> encapsulate PERF_MEM_EVENTS__MAX into perf_mem_events__ptr(), thus
> builtin-mem.c and buildin-c2c.c are not necessary to use
> PERF_MEM_EVENTS__MAX in the loop and only needs to detect if the
> pointer is NULL or not when return from perf_mem_events__ptr().

ah because u added that load_store event

> 
> How about change as below?
> 
>         for (j = 0; (e = perf_mem_events__ptr(j)) != NULL; j++) {
>                 [...]

will this work? e will be NULL for first iteration no?

there are still other for loops with PERF_MEM_EVENTS__MAX used
in the patch.. you overload the perf_mem_events access for arm,
and add missing load_store NULL item to generic version, so there's
always PERF_MEM_EVENTS__MAX items in the array

can we just use the current for loop and check for e->tag != NULL
or any other field

thanks,
jirka


  reply	other threads:[~2020-09-04 15:53 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-01  8:38 [PATCH v2 00/14] perf mem: Support AUX trace and Arm SPE Leo Yan
2020-09-01  8:38 ` [PATCH v2 01/14] perf mem: Search event name with more flexible path Leo Yan
2020-09-03 13:50   ` Jiri Olsa
2020-09-01  8:38 ` [PATCH v2 02/14] perf mem: Introduce weak function perf_mem_events__ptr() Leo Yan
2020-09-03 13:50   ` Jiri Olsa
2020-09-04  0:34     ` Leo Yan
2020-09-04 15:52       ` Jiri Olsa [this message]
2020-09-07  8:17         ` Leo Yan
2020-09-01  8:38 ` [PATCH v2 03/14] perf mem: Support new memory event PERF_MEM_EVENTS__LOAD_STORE Leo Yan
2020-09-01  8:38 ` [PATCH v2 04/14] perf mem: Only initialize memory event for recording Leo Yan
2020-09-01  8:38 ` [PATCH v2 05/14] perf auxtrace: Add option '-M' for memory events Leo Yan
2020-09-01  8:38 ` [PATCH v2 06/14] perf mem: Support AUX trace Leo Yan
2020-09-01  8:38 ` [PATCH v2 07/14] perf mem: Support Arm SPE events Leo Yan
2020-09-01  8:38 ` [PATCH v2 08/14] perf arm-spe: Enable attribution PERF_SAMPLE_DATA_SRC Leo Yan
2020-09-01  8:38 ` [PATCH v2 09/14] perf arm-spe: Save memory addresses in packet Leo Yan
2020-09-01  8:38 ` [PATCH v2 10/14] perf arm-spe: Store operation types " Leo Yan
2020-09-01  8:38 ` [PATCH v2 11/14] perf arm-spe: Fill address info for samples Leo Yan
2020-09-01  8:38 ` [PATCH v2 12/14] perf arm-spe: Synthesize memory event Leo Yan
2020-09-01  8:38 ` [PATCH v2 13/14] perf arm-spe: Set sample's data source field Leo Yan
2020-09-01  8:38 ` [PATCH v2 14/14] perf mem: Document options introduced by Arm SPE Leo Yan

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