[LTP] [PATCH] open_posix_testsuite: add set_affinity_single()

[Jan Stancek <jstancek@redhat.com>]

----- Original Message -----
> From: "Jan Stancek" <jstancek@redhat.com>
> To: ltp@lists.linux.it
> Sent: Thursday, 12 November, 2015 1:45:47 PM
> Subject: [LTP] [PATCH] open_posix_testsuite: add set_affinity_single()
> 
> Couple testcases rely on set_affinity(), to limit usage of CPUs
> to a single one. However they hardcode CPU number to "0", which
> is causing problems on systems where CPU0 is not available (for
> example it's offline, etc.)
> 
> This patch adds set_affinity_single() (which sets affinity to
> first single present CPU) and replaces all calls to set_affinity(0).
> 
> Signed-off-by: Jan Stancek <jstancek@redhat.com>
> ---
>  .../interfaces/pthread_attr_setschedpolicy/2-1.c   |  4 +-
>  .../conformance/interfaces/pthread_create/1-6.c    |  2 +-
>  .../conformance/interfaces/sched_setparam/2-1.c    |  2 +-
>  .../conformance/interfaces/sched_setparam/2-2.c    |  2 +-
>  .../conformance/interfaces/sched_setparam/9-1.c    |  2 +-
>  .../conformance/interfaces/sched_yield/1-1.c       |  4 +-
>  testcases/open_posix_testsuite/include/affinity.h  | 54
>  ++++++++++++++++++++++
>  7 files changed, 62 insertions(+), 8 deletions(-)
> 
> diff --git
> a/testcases/open_posix_testsuite/conformance/interfaces/pthread_attr_setschedpolicy/2-1.c
> b/testcases/open_posix_testsuite/conformance/interfaces/pthread_attr_setschedpolicy/2-1.c
> index 426988b44eb6..3c4cec77277f 100644
> ---
> a/testcases/open_posix_testsuite/conformance/interfaces/pthread_attr_setschedpolicy/2-1.c
> +++
> b/testcases/open_posix_testsuite/conformance/interfaces/pthread_attr_setschedpolicy/2-1.c
> @@ -150,9 +150,9 @@ int main(void)
>  	status = PTS_UNRESOLVED;
>  
>  
> -	rc = set_affinity(0);
> +	rc = set_affinity_single();
>  	if (rc)
> -		FAIL_AND_EXIT("set_affinity", errno);
> +		FAIL_AND_EXIT("set_affinity_single", errno);
>  
>  	sp.sched_priority = PRIO_MAIN;
>  	rc = pthread_setschedparam(pthread_self(), SCHED_FIFO, &sp);
> diff --git
> a/testcases/open_posix_testsuite/conformance/interfaces/pthread_create/1-6.c
> b/testcases/open_posix_testsuite/conformance/interfaces/pthread_create/1-6.c
> index 11654dfc00bf..03c266a4adc9 100644
> ---
> a/testcases/open_posix_testsuite/conformance/interfaces/pthread_create/1-6.c
> +++
> b/testcases/open_posix_testsuite/conformance/interfaces/pthread_create/1-6.c
> @@ -238,7 +238,7 @@ int main(void)
>  	int ret;
>  	unsigned int i;
>  
> -	ret = set_affinity(0);
> +	ret = set_affinity_single();
>  	if (ret) {
>  		n_threads = get_ncpu();
>  		if (n_threads == -1) {
> diff --git
> a/testcases/open_posix_testsuite/conformance/interfaces/sched_setparam/2-1.c
> b/testcases/open_posix_testsuite/conformance/interfaces/sched_setparam/2-1.c
> index 10de0afe5e90..86cf3a726893 100644
> ---
> a/testcases/open_posix_testsuite/conformance/interfaces/sched_setparam/2-1.c
> +++
> b/testcases/open_posix_testsuite/conformance/interfaces/sched_setparam/2-1.c
> @@ -93,7 +93,7 @@ int main(void)
>  	   There is no guarantee that the LOOP of the child
>  	   can be certainly big enough on any device at any time.
>  	 */
> -	int rc = set_affinity(0);
> +	int rc = set_affinity_single();
>  	if (rc) {
>  		nb_child = get_ncpu();
>  		if (nb_child == -1) {
> diff --git
> a/testcases/open_posix_testsuite/conformance/interfaces/sched_setparam/2-2.c
> b/testcases/open_posix_testsuite/conformance/interfaces/sched_setparam/2-2.c
> index 4b14691d9200..746f9a107217 100644
> ---
> a/testcases/open_posix_testsuite/conformance/interfaces/sched_setparam/2-2.c
> +++
> b/testcases/open_posix_testsuite/conformance/interfaces/sched_setparam/2-2.c
> @@ -94,7 +94,7 @@ int main(void)
>  	   There is no guarantee that the LOOP of the child
>  	   can be certainly big enough on any device at any time.
>  	 */
> -	int rc = set_affinity(0);
> +	int rc = set_affinity_single();
>  	if (rc) {
>  		nb_child = get_ncpu();
>  		if (nb_child == -1) {
> diff --git
> a/testcases/open_posix_testsuite/conformance/interfaces/sched_setparam/9-1.c
> b/testcases/open_posix_testsuite/conformance/interfaces/sched_setparam/9-1.c
> index c3e4f1c113c3..32f3e5be4501 100644
> ---
> a/testcases/open_posix_testsuite/conformance/interfaces/sched_setparam/9-1.c
> +++
> b/testcases/open_posix_testsuite/conformance/interfaces/sched_setparam/9-1.c
> @@ -109,7 +109,7 @@ int main(void)
>  	int *child_pid, oldcount, newcount, shm_id, i;
>  	struct sched_param param;
>  	key_t key;
> -	int rc = set_affinity(0);
> +	int rc = set_affinity_single();
>  	if (rc) {
>  		nb_cpu = get_ncpu();
>  		if (nb_cpu == -1) {
> diff --git
> a/testcases/open_posix_testsuite/conformance/interfaces/sched_yield/1-1.c
> b/testcases/open_posix_testsuite/conformance/interfaces/sched_yield/1-1.c
> index 621b9deaaf3d..602733e608ae 100644
> --- a/testcases/open_posix_testsuite/conformance/interfaces/sched_yield/1-1.c
> +++ b/testcases/open_posix_testsuite/conformance/interfaces/sched_yield/1-1.c
> @@ -85,9 +85,9 @@ int main(void)
>  	}
>  
>  	/* Must only use a single CPU */
> -	rc = set_affinity(0);
> +	rc = set_affinity_single();
>  	if (rc) {
> -		ERR_LOG("set_affinity", rc);
> +		ERR_LOG("set_affinity_single", rc);
>  		return status;
>  	}
>  
> diff --git a/testcases/open_posix_testsuite/include/affinity.h
> b/testcases/open_posix_testsuite/include/affinity.h
> index 64be34d04e55..f89101645cb5 100644
> --- a/testcases/open_posix_testsuite/include/affinity.h
> +++ b/testcases/open_posix_testsuite/include/affinity.h
> @@ -27,6 +27,7 @@
>  # define _GNU_SOURCE
>  # define AFFINITY_NEEDS_GNU_SOURCE 1
>  # include <sched.h>
> +# include <stdio.h>
>  
>  static int set_affinity(int cpu)
>  {
> @@ -37,6 +38,59 @@ static int set_affinity(int cpu)
>  
>  	return (sched_setaffinity(0, sizeof(cpu_set_t), &mask));
>  }
> +
> +static int get_present_cpu_from_sysfs(void)
> +{
> +	FILE *f;
> +	int cpu = -1;
> +
> +	f = fopen("/sys/devices/system/cpu/present", "r");

This should have been "online", not present. I'll fix that in v2.

> +	if (!f)
> +		return -1;
> +	fscanf(f, "%d", &cpu);
> +	fclose(f);
> +
> +	return cpu;
> +}
> +
> +static int get_present_cpu_from_cpuinfo(void)
> +{
> +	FILE *f;
> +	int cpu = -1;
> +	char line[4096];
> +
> +	f = fopen("/proc/cpuinfo", "r");
> +	if (!f)
> +		return -1;
> +
> +	while (!feof(f)) {
> +		if (!fgets(line, sizeof(line), f))
> +			return -1;
> +		/*
> +		 * cpuinfo output is not consistent across all archictures,
> +		 * it can be "processor        : N", but for example on s390
> +		 * it's: "processor N: ...", so ignore any non-number
> +		 * after "processor"
> +		 */
> +		if (sscanf(line, "processor%*[^0123456789]%d", &cpu) == 1)
> +			break;
> +	}
> +	fclose(f);
> +
> +	return cpu;
> +}
> +
> +static int set_affinity_single(void)
> +{
> +	int cpu;
> +
> +	cpu = get_present_cpu_from_sysfs();
> +	if (cpu < 0)
> +		cpu = get_present_cpu_from_cpuinfo();
> +
> +	return set_affinity(cpu);
> +}
> +
>  #else
>  static int set_affinity(int cpu)
>  {
> --
> 1.8.3.1
> 
> 
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>