Re: [PATCH 2/3] tests/gem_close_race: Adapt the test for Full PPGTT

[Daniel Vetter <daniel@ffwll.ch>]

On Tue, Dec 10, 2013 at 09:36:22AM +0000, oscar.mateo@intel.com wrote:
> From: Oscar Mateo <oscar.mateo@intel.com>
> 
> With Full PPGTT, each new fd creates a new context and thus a new
> PPGTT, so we have to reduce the number of simultaneous fds or face
> OOM problems. For every new PPGTT, its PDEs are stored in the GGTT
> which imposes a limit of 1024 new contexts. We want to leave at
> least 1/4 of the GGTT available for "important" stuff like scanout
> buffers, so never open more than 768 fds.
> 
> Signed-off-by: Oscar Mateo <oscar.mateo@intel.com>

This test hasn't been terribly effective at provoking the bug it tries to
hit, so I think we can just unconditionally use the lower limit. That also
helps with the really long runtime of this case a bit.
-Daniel

> ---
>  tests/gem_close_race.c |   39 ++++++++++++++++++++++++++-------------
>  1 file changed, 26 insertions(+), 13 deletions(-)
> 
> diff --git a/tests/gem_close_race.c b/tests/gem_close_race.c
> index 6064c02..f658c90 100644
> --- a/tests/gem_close_race.c
> +++ b/tests/gem_close_race.c
> @@ -49,6 +49,8 @@
>  
>  static char device[80];
>  static uint32_t devid;
> +static unsigned int num_childs = 2000;
> +static unsigned int num_fds = 32000;
>  
>  static void selfcopy(int fd, uint32_t handle, int loops)
>  {
> @@ -136,11 +138,10 @@ static void run(int child)
>  		gem_read(fd, handle, 0, &handle, sizeof(handle));
>  }
>  
> -#define NUM_FD 32000
> -
>  struct thread {
>  	pthread_mutex_t mutex;
> -	int fds[NUM_FD];
> +	unsigned int num_fds;
> +	int *fds;
>  	int done;
>  };
>  
> @@ -152,7 +153,7 @@ static void *thread_run(void *_data)
>  	while (!t->done) {
>  		pthread_mutex_unlock(&t->mutex);
>  
> -		for (int n = 0; n < NUM_FD; n++) {
> +		for (int n = 0; n < t->num_fds; n++) {
>  			struct drm_i915_gem_create create;
>  
>  			create.handle = 0;
> @@ -185,7 +186,7 @@ static void *thread_busy(void *_data)
>  
>  		pthread_mutex_unlock(&t->mutex);
>  
> -		n  = rand() % NUM_FD;
> +		n  = rand() % t->num_fds;
>  
>  		create.handle = 0;
>  		create.size = OBJECT_SIZE;
> @@ -213,16 +214,23 @@ igt_main
>  {
>  	igt_skip_on_simulation();
>  
> -	sprintf(device, "/dev/dri/card%d", drm_get_card());
> -	{
> -		int fd = open(device, O_RDWR);
> +	igt_fixture {
> +		int fd;
> +		sprintf(device, "/dev/dri/card%d", drm_get_card());
> +		fd = open(device, O_RDWR);
>  		igt_assert(fd != -1);
>  		devid = intel_get_drm_devid(fd);
> +		if (gem_uses_full_ppgtt(fd))
> +		{
> +			/* Reduce the number of simultaneous fds or face OOM */
> +			num_childs = 768;
> +			num_fds = 768;
> +		}
>  		close(fd);
>  	}
>  
>  	igt_subtest("process-exit") {
> -		igt_fork(child, 2000)
> +		igt_fork(child, num_childs)
>  			run(child);
>  		igt_waitchildren();
>  	}
> @@ -232,17 +240,21 @@ igt_main
>  		struct thread *data = calloc(1, sizeof(struct thread));
>  		int n;
>  
> +		data->num_fds = num_fds;
> +		data->fds = calloc(num_fds, sizeof(int));
> +
>  		igt_assert(data);
> +		igt_assert(data->fds);
>  
>  		pthread_mutex_init(&data->mutex, NULL);
> -		for (n = 0; n < NUM_FD; n++)
> +		for (n = 0; n < num_fds; n++)
>  			data->fds[n] = open(device, O_RDWR);
>  
>  		pthread_create(&thread[0], NULL, thread_run, data);
>  		pthread_create(&thread[1], NULL, thread_busy, data);
>  
> -		for (n = 0; n < 1000*NUM_FD; n++) {
> -			int i = rand() % NUM_FD;
> +		for (n = 0; n < 1000*num_fds; n++) {
> +			int i = rand() % num_fds;
>  			if (data->fds[i] == -1) {
>  				data->fds[i] = open(device, O_RDWR);
>  			} else{
> @@ -258,8 +270,9 @@ igt_main
>  		pthread_join(thread[1], NULL);
>  		pthread_join(thread[0], NULL);
>  
> -		for (n = 0; n < NUM_FD; n++)
> +		for (n = 0; n < num_fds; n++)
>  			close(data->fds[n]);
> +		free(data->fds);
>  		free(data);
>  	}
>  }
> -- 
> 1.7.9.5
> 
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch