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Date: Wed, 3 Jun 2026 15:54:15 +0100
From: Leo Yan <leo.yan@arm.com>
To: James Clark <james.clark@linaro.org>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>,
	Mike Leach <mike.leach@arm.com>,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	Namhyung Kim <namhyung@kernel.org>, Jiri Olsa <jolsa@kernel.org>,
	Ian Rogers <irogers@google.com>, Amir Ayupov <aaupov@meta.com>,
	Jonathan Corbet <corbet@lwn.net>,
	Shuah Khan <skhan@linuxfoundation.org>,
	Paschalis Mpeis <Paschalis.Mpeis@arm.com>,
	coresight@lists.linaro.org, linux-perf-users@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	Arnaldo Carvalho de Melo <acme@redhat.com>,
	linux-doc@vger.kernel.org
Subject: Re: [PATCH v2 09/18] perf test: Add named_threads workload
Message-ID: <20260603145415.GY101133@e132581.arm.com>
References: <20260602-james-cs-context-tracking-fix-v2-0-85b5ce6f55c6@linaro.org>
 <20260602-james-cs-context-tracking-fix-v2-9-85b5ce6f55c6@linaro.org>
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In-Reply-To: <20260602-james-cs-context-tracking-fix-v2-9-85b5ce6f55c6@linaro.org>

On Tue, Jun 02, 2026 at 03:26:51PM +0100, James Clark wrote:

> +#define DEFINE_THREAD(n)						\
> +noinline void *named_threads_thread##n(void *arg __maybe_unused)	\
> +{									\
> +	pthread_setname_np(pthread_self(), "thread" #n);		\
> +	for (int i = 0; i < iterations; i++)				\
> +		named_threads_work *= 3;				\
> +									\
> +	return NULL;							\
> +}

> +static int named_threads(int argc, const char **argv)
> +{
> +	pthread_t threads[MAX_THREADS];
> +	int nr_threads = 1;
> +	int err = 0;
> +
> +	if (argc > 0)
> +		nr_threads = atoi(argv[0]);
> +
> +	if (nr_threads <= 0 || nr_threads > MAX_THREADS) {
> +		fprintf(stderr, "Error: num threads must be 1 - %d\n", MAX_THREADS);
> +		return 1;
> +	}
> +
> +	if (argc > 1)
> +		iterations = atoi(argv[1]);
> +
> +	if (iterations < 0) {
> +		fprintf(stderr, "Error: iterations must be non-negative\n");
> +		return 1;
> +	}
> +
> +	for (int i = 0; i < nr_threads; i++) {
> +		int ret;
> +
> +		ret = pthread_create(&threads[i], NULL, thread_fns[i], NULL);

Just curious this can be simplified to a thread function, like:

  noinline void *named_thread(void *arg)
  {
        char name[16];

        snprintf(name, sizeof(name), "thread%d", int(arg));

  	pthread_setname_np(pthread_self(), name);
        ...
  	return NULL;
  }

Thanks,
Leo