[igt-dev] [PATCH igt] igt/perf_pmu: Disable all cpus
Tvrtko Ursulin
tvrtko.ursulin at linux.intel.com
Wed Feb 21 09:11:15 UTC 2018
On 20/02/2018 21:40, Chris Wilson wrote:
> 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,
Hm, interesting and I think it possibly makes sense to test both
migration patterns.
> immediately reboot the system.
Yes, we already agreed on this one and I was planning to do it so thanks
for beating me to it.
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Tvrtko Ursulin <tvrtko.ursulin at 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;
Keep off-lining until no more CPUs to offline? I had to try it! :) Ok,
last one will fail to offline. But I think it needs a comment.
> - }
>
> - /* 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);
Need to online in the same order or the PMU will stay on some higher CPU
making the subsequent tests fail. Or I need to improve the helpers to
hunt for the correct CPU, as perf tool does.
> - 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]);
>
Regards,
Tvrtko
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