[PATCH igt] igt/perf_pmu: Disable all cpus

* [PATCH igt] igt/perf_pmu: Disable all cpus
@ 2018-02-20 21:40 ` Chris Wilson
  0 siblings, 0 replies; 12+ messages in thread
From: Chris Wilson @ 2018-02-20 21:40 UTC (permalink / raw)
  To: intel-gfx; +Cc: igt-dev

Rather than iteratively disable and then immediately reenable a CPU,
turn off each in turn, forcing the PMU events onto the next CPU without
allowing them to retreat back to CPU0 after the first. If this fails,
immediately reboot the system.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
---
 lib/Makefile.sources |  2 ++
 lib/igt_sysrq.c      | 20 ++++++++++++++++++
 lib/igt_sysrq.h      | 30 +++++++++++++++++++++++++++
 lib/meson.build      |  2 ++
 tests/perf_pmu.c     | 57 ++++++++++++++++++++++++++++++++++------------------
 5 files changed, 92 insertions(+), 19 deletions(-)
 create mode 100644 lib/igt_sysrq.c
 create mode 100644 lib/igt_sysrq.h

diff --git a/lib/Makefile.sources b/lib/Makefile.sources
index 86fbfeef..e4a9b059 100644
--- a/lib/Makefile.sources
+++ b/lib/Makefile.sources
@@ -33,6 +33,8 @@ lib_source_list =	 	\
 	igt_stats.h		\
 	igt_sysfs.c		\
 	igt_sysfs.h		\
+	igt_sysrq.c		\
+	igt_sysrq.h		\
 	igt_x86.h		\
 	igt_x86.c		\
 	igt_vgem.c		\
diff --git a/lib/igt_sysrq.c b/lib/igt_sysrq.c
new file mode 100644
index 00000000..32fb4a39
--- /dev/null
+++ b/lib/igt_sysrq.c
@@ -0,0 +1,20 @@
+#include <unistd.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <sys/reboot.h>
+
+#include "igt_sysrq.h"
+
+void igt_sysrq_reboot(void)
+{
+	sync();
+
+	/* Try to be nice at first, and if that fails pull the trigger */
+	if (reboot(RB_AUTOBOOT)) {
+		int fd = open("/proc/sysrq-trigger", O_WRONLY);
+		write(fd, "b", 2);
+		close(fd);
+	}
+
+	abort();
+}
diff --git a/lib/igt_sysrq.h b/lib/igt_sysrq.h
new file mode 100644
index 00000000..422473d2
--- /dev/null
+++ b/lib/igt_sysrq.h
@@ -0,0 +1,30 @@
+/*
+ * Copyright © 2018 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ *
+ */
+
+#ifndef __IGT_SYSRQ_H__
+#define __IGT_SYSRQ_H__
+
+void igt_sysrq_reboot(void) __attribute__((noreturn));
+
+#endif /* __IGT_SYSRQ_H__ */
diff --git a/lib/meson.build b/lib/meson.build
index 94ea0799..2c611348 100644
--- a/lib/meson.build
+++ b/lib/meson.build
@@ -21,6 +21,7 @@ lib_headers = [
 	'igt_stats.h',
 	'igt_syncobj.h',
 	'igt_sysfs.h',
+	'igt_sysrq.h',
 	'igt_x86.h',
 	'igt_vgem.h',
 	'instdone.h',
@@ -67,6 +68,7 @@ lib_sources = [
 	'igt_stats.c',
 	'igt_syncobj.c',
 	'igt_sysfs.c',
+	'igt_sysrq.c',
 	'igt_vgem.c',
 	'igt_x86.c',
 	'instdone.c',
diff --git a/tests/perf_pmu.c b/tests/perf_pmu.c
index 7fab73e2..1421fd9a 100644
--- a/tests/perf_pmu.c
+++ b/tests/perf_pmu.c
@@ -41,6 +41,7 @@
 #include "igt_core.h"
 #include "igt_perf.h"
 #include "igt_sysfs.h"
+#include "igt_sysrq.h"
 #include "igt_pm.h"
 #include "sw_sync.h"
 
@@ -957,6 +958,16 @@ static bool cpu0_hotplug_support(void)
 	return access("/sys/devices/system/cpu/cpu0/online", W_OK) == 0;
 }
 
+static int open_cpu_online(int cpu)
+{
+	char name[128];
+
+	igt_assert_lt(snprintf(name, sizeof(name),
+			       "/sys/devices/system/cpu/cpu%d/online",
+			       cpu), sizeof(name));
+	return open(name, O_WRONLY);
+}
+
 static void cpu_hotplug(int gem_fd)
 {
 	igt_spin_t *spin[2];
@@ -988,35 +999,43 @@ static void cpu_hotplug(int gem_fd)
 	 */
 	igt_fork(child, 1) {
 		int cpu = 0;
+		int cpufd;
+		int err;
 
 		close(link[0]);
 
+		/* Offline each cpu in turn */
 		for (;;) {
-			char name[128];
-			int cpufd;
-
-			igt_assert_lt(snprintf(name, sizeof(name),
-					       "/sys/devices/system/cpu/cpu%d/online",
-					       cpu), sizeof(name));
-			cpufd = open(name, O_WRONLY);
-			if (cpufd == -1) {
-				igt_assert(cpu > 0);
-				/*
-				 * Signal parent that we cycled through all
-				 * CPUs and we are done.
-				 */
-				igt_assert_eq(write(link[1], "*", 1), 1);
+			cpufd = open_cpu_online(cpu);
+			igt_assert(cpufd != -1);
+
+			err = write(cpufd, "0", 2);
+			close(cpufd);
+			if (err < 0)
 				break;
-			}
 
-			/* Offline followed by online a CPU. */
-			igt_assert_eq(write(cpufd, "0", 2), 2);
 			usleep(1e6);
-			igt_assert_eq(write(cpufd, "1", 2), 2);
+			cpu++;
+		}
 
+		/* Then bring them back online */
+		while (cpu--) {
+			cpufd = open_cpu_online(cpu);
+			err = write(cpufd, "1", 2);
 			close(cpufd);
-			cpu++;
+
+			if (err < 0) {
+				igt_warn("Failed to bring CPU%d back online\n",
+					 cpu);
+				igt_sysrq_reboot();
+			}
 		}
+
+		/*
+		 * Signal parent that we cycled through all
+		 * CPUs and we are done.
+		 */
+		igt_assert_eq(write(link[1], "*", 1), 1);
 	}
 
 	close(link[1]);
-- 
2.16.1

_______________________________________________
Intel-gfx mailing list
Intel-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/intel-gfx

^ permalink raw reply related	[flat|nested] 12+ messages in thread