Attachment 125128 Details for Bug 96701 – Fix missed page flip error in basic_cursor_vs_flip

[patch] Fix missed page flip error in basic_cursor_vs_flip

0001-kms_cursor_legacy-Fix-mutex-starvation.patch (text/plain), 3.92 KB, created by Imre Deak on 2016-07-18 08:05:43 UTC

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Creator: Imre Deak

Created: 2016-07-18 08:05:43 UTC

Size: 3.92 KB

patch

obsolete

>From 463408146a9c3f47a82baf246d8a33c72395d251 Mon Sep 17 00:00:00 2001
>From: Imre Deak <imre.deak@intel.com>
>Date: Sun, 17 Jul 2016 23:58:56 +0300
>Subject: [PATCH] kms_cursor_legacy: Fix mutex starvation
>
>Signed-off-by: Imre Deak <imre.deak@intel.com>
>---
> tests/kms_cursor_legacy.c | 63 ++++++++++++++++++++++++++++++++++++++++-------
> 1 file changed, 54 insertions(+), 9 deletions(-)
>
>diff --git a/tests/kms_cursor_legacy.c b/tests/kms_cursor_legacy.c
>index 7dca383..15e071d 100644
>--- a/tests/kms_cursor_legacy.c
>+++ b/tests/kms_cursor_legacy.c
>@@ -24,6 +24,7 @@
> 
> #define _GNU_SOURCE
> #include <sched.h>
>+#include <pthread.h>
> 
> #include "igt.h"
> #include "igt_rand.h"
>@@ -347,11 +348,17 @@ static void basic_cursor_vs_flip(struct data *data, int nloops)
> 	struct drm_event_vblank vbl;
> 	struct igt_fb fb_info;
> 	unsigned vblank_start, vblank_last;
>-	volatile unsigned long *shared;
>+	struct {
>+		volatile unsigned long count;
>+		volatile bool flipping;
>+		pthread_mutex_t mutex;
>+		pthread_cond_t cond;
>+	} *shared;
> 	int target;
> 	uint32_t fb_id;
> 
>-	shared = mmap(NULL, 4096, PROT_WRITE, MAP_SHARED | MAP_ANON, -1, 0);
>+	shared = mmap(NULL, sizeof(*shared), PROT_WRITE, MAP_SHARED | MAP_ANON, 
>+		      -1, 0);
> 	igt_assert(shared != MAP_FAILED);
> 
> 	memset(&arg, 0, sizeof(arg));
>@@ -384,23 +391,61 @@ static void basic_cursor_vs_flip(struct data *data, int nloops)
> 		  target);
> 
> 	for (int i = 0; i < nloops; i++) {
>-		shared[0] = 0;
>+		pthread_mutexattr_t mutex_attr;
>+		pthread_condattr_t cond_attr;
>+
>+		shared->count = 0;
>+		shared->flipping = false;
>+
>+		pthread_mutexattr_init(&mutex_attr);
>+		pthread_mutexattr_setpshared(&mutex_attr,
>+					     PTHREAD_PROCESS_SHARED);
>+		pthread_mutex_init(&shared->mutex, &mutex_attr);
>+
>+		pthread_condattr_init(&cond_attr);
>+		pthread_condattr_setpshared(&cond_attr,
>+					     PTHREAD_PROCESS_SHARED);
>+		pthread_cond_init(&shared->cond, &cond_attr);
>+
> 		igt_fork(child, 1) {
> 			unsigned long count = 0;
>-			while (!shared[0]) {
>+
>+			while (!shared->count) {
>+				pthread_mutex_lock(&shared->mutex);
>+				while (shared->flipping)
>+					pthread_cond_wait(&shared->cond,
>+							  &shared->mutex);
>+				pthread_mutex_unlock(&shared->mutex);
>+
> 				drmIoctl(data->fd, DRM_IOCTL_MODE_CURSOR, &arg);
>+
> 				count++;
> 			}
> 			igt_debug("child: %lu cursor updates\n", count);
>-			shared[0] = count;
>+			shared->count = count;
> 		}
>+
>+		shared->flipping = true;
>+
> 		do_or_die(drmModePageFlip(data->fd, arg.crtc_id, fb_id,
> 					DRM_MODE_PAGE_FLIP_EVENT, &fb_id));
>+
>+		pthread_mutex_lock(&shared->mutex);
>+		shared->flipping = false;
>+		pthread_cond_signal(&shared->cond);
>+		pthread_mutex_unlock(&shared->mutex);
>+
> 		igt_assert_eq(read(data->fd, &vbl, sizeof(vbl)), sizeof(vbl));
> 		vblank_start = vblank_last = vbl.sequence;
> 		for (int n = 0; n < 60; n++) {
>+			shared->flipping = true;
> 			do_or_die(drmModePageFlip(data->fd, arg.crtc_id, fb_id,
> 						DRM_MODE_PAGE_FLIP_EVENT, &fb_id));
>+			pthread_mutex_lock(&shared->mutex);
>+			shared->flipping = false;
>+			pthread_cond_signal(&shared->cond);
>+			pthread_mutex_unlock(&shared->mutex);
>+
> 			igt_assert_eq(read(data->fd, &vbl, sizeof(vbl)), sizeof(vbl));
> 			if (vbl.sequence != vblank_last + 1) {
> 				igt_warn("page flip %d was delayed, missed %d frames\n",
>@@ -410,18 +455,18 @@ static void basic_cursor_vs_flip(struct data *data, int nloops)
> 		}
> 		igt_assert_eq(vbl.sequence, vblank_start + 60);
> 
>-		shared[0] = 1;
>+		shared->count = 1;
> 		igt_waitchildren();
>-		igt_assert_f(shared[0] > 60*target,
>+		igt_assert_f(shared->count > 60*target,
> 			     "completed %lu cursor updated in a period of 60 flips, "
> 			     "we expect to complete approximately %lu updateds, "
> 			     "with the threshold set at %lu\n",
>-			     shared[0], 2*60ul*target, 60ul*target);
>+			     shared->count, 2*60ul*target, 60ul*target);
> 	}
> 
> 	igt_remove_fb(data->fd, &fb_info);
> 	gem_close(data->fd, arg.handle);
>-	munmap((void *)shared, 4096);
>+	munmap((void *)shared, sizeof(*shared));
> }
> 
> igt_main
>-- 
>2.7.4
>

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Attachments on bug 96701: 124746 | 124907 | 125059 | 125128 | 125229 | 125230 | 125685 | 125686

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