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Date: Sun, 14 Jan 2024 23:17:11 +0900
From: Masami Hiramatsu (Google) <mhiramat@...nel.org>
To: Masami Hiramatsu (Google) <mhiramat@...nel.org>
Cc: Vincent Donnefort <vdonnefort@...gle.com>, rostedt@...dmis.org,
linux-kernel@...r.kernel.org, linux-trace-kernel@...r.kernel.org,
mathieu.desnoyers@...icios.com, kernel-team@...roid.com, Shuah Khan
<shuah@...nel.org>, Shuah Khan <skhan@...uxfoundation.org>,
linux-kselftest@...r.kernel.org
Subject: Re: [PATCH v11 5/5] ring-buffer/selftest: Add ring-buffer mapping
test
Hi Vincent,
On Sat, 13 Jan 2024 22:39:46 +0900
Masami Hiramatsu (Google) <mhiramat@...nel.org> wrote:
> On Thu, 11 Jan 2024 16:17:12 +0000
> Vincent Donnefort <vdonnefort@...gle.com> wrote:
>
> > This test maps a ring-buffer and validate the meta-page after reset and
> > after emitting few events.
> >
> > Cc: Shuah Khan <shuah@...nel.org>
> > Cc: Shuah Khan <skhan@...uxfoundation.org>
> > Cc: linux-kselftest@...r.kernel.org
> > Signed-off-by: Vincent Donnefort <vdonnefort@...gle.com>
>
> Looks good to me and tested.
>
> Reviewed-by: Masami Hiramatsu (Google) <mhiramat@...nel.org>
> Tested-by: Masami Hiramatsu (Google) <mhiramat@...nel.org>
Sorry, I should cancel these. I found this test did not pass if I set
the function tracer on.
/ # cd /sys/kernel/tracing/
/sys/kernel/tracing # echo function > current_tracer
/sys/kernel/tracing # /mnt/map_test
TAP version 13
1..2
# Starting 2 tests from 2 test cases.
# RUN map.subbuf_size_4k.meta_page_check ...
# map_test.c:174:meta_page_check:Expected self->meta->entries (15293) == 16 (16)
# meta_page_check: Test terminated by assertion
# FAIL map.subbuf_size_4k.meta_page_check
not ok 1 map.subbuf_size_4k.meta_page_check
# RUN map.subbuf_size_8k.meta_page_check ...
# map_test.c:174:meta_page_check:Expected self->meta->entries (15270) == 16 (16)
# meta_page_check: Test terminated by assertion
# FAIL map.subbuf_size_8k.meta_page_check
not ok 2 map.subbuf_size_8k.meta_page_check
# FAILED: 0 / 2 tests passed.
# Totals: pass:0 fail:2 xfail:0 xpass:0 skip:0 error:0
Does this depend on "nop" tracer?
Thank you,
>
> Thank you,
>
> >
> > diff --git a/tools/testing/selftests/ring-buffer/Makefile b/tools/testing/selftests/ring-buffer/Makefile
> > new file mode 100644
> > index 000000000000..627c5fa6d1ab
> > --- /dev/null
> > +++ b/tools/testing/selftests/ring-buffer/Makefile
> > @@ -0,0 +1,8 @@
> > +# SPDX-License-Identifier: GPL-2.0
> > +CFLAGS += -Wl,-no-as-needed -Wall
> > +CFLAGS += $(KHDR_INCLUDES)
> > +CFLAGS += -D_GNU_SOURCE
> > +
> > +TEST_GEN_PROGS = map_test
> > +
> > +include ../lib.mk
> > diff --git a/tools/testing/selftests/ring-buffer/config b/tools/testing/selftests/ring-buffer/config
> > new file mode 100644
> > index 000000000000..ef8214661612
> > --- /dev/null
> > +++ b/tools/testing/selftests/ring-buffer/config
> > @@ -0,0 +1 @@
> > +CONFIG_FTRACE=y
> > diff --git a/tools/testing/selftests/ring-buffer/map_test.c b/tools/testing/selftests/ring-buffer/map_test.c
> > new file mode 100644
> > index 000000000000..49107e8da5e9
> > --- /dev/null
> > +++ b/tools/testing/selftests/ring-buffer/map_test.c
> > @@ -0,0 +1,188 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Ring-buffer memory mapping tests
> > + *
> > + * Copyright (c) 2024 Vincent Donnefort <vdonnefort@...gle.com>
> > + */
> > +#include <fcntl.h>
> > +#include <sched.h>
> > +#include <stdbool.h>
> > +#include <stdio.h>
> > +#include <stdlib.h>
> > +#include <unistd.h>
> > +
> > +#include <linux/trace_mmap.h>
> > +
> > +#include <sys/mman.h>
> > +#include <sys/ioctl.h>
> > +
> > +#include "../user_events/user_events_selftests.h" /* share tracefs setup */
> > +#include "../kselftest_harness.h"
> > +
> > +#define TRACEFS_ROOT "/sys/kernel/tracing"
> > +
> > +static int __tracefs_write(const char *path, const char *value)
> > +{
> > + FILE *file;
> > +
> > + file = fopen(path, "w");
> > + if (!file)
> > + return -1;
> > +
> > + fputs(value, file);
> > + fclose(file);
> > +
> > + return 0;
> > +}
> > +
> > +static int __tracefs_write_int(const char *path, int value)
> > +{
> > + char *str;
> > + int ret;
> > +
> > + if (asprintf(&str, "%d", value) < 0)
> > + return -1;
> > +
> > + ret = __tracefs_write(path, str);
> > +
> > + free(str);
> > +
> > + return ret;
> > +}
> > +
> > +#define tracefs_write_int(path, value) \
> > + ASSERT_EQ(__tracefs_write_int((path), (value)), 0)
> > +
> > +static int tracefs_reset(void)
> > +{
> > + if (__tracefs_write_int(TRACEFS_ROOT"/tracing_on", 0))
> > + return -1;
> > + if (__tracefs_write_int(TRACEFS_ROOT"/trace", 0))
> > + return -1;
> > + if (__tracefs_write(TRACEFS_ROOT"/set_event", ""))
> > + return -1;
> > +
> > + return 0;
> > +}
> > +
> > +FIXTURE(map) {
> > + struct trace_buffer_meta *meta;
> > + void *data;
> > + int cpu_fd;
> > + bool umount;
> > +};
> > +
> > +FIXTURE_VARIANT(map) {
> > + int subbuf_size;
> > +};
> > +
> > +FIXTURE_VARIANT_ADD(map, subbuf_size_4k) {
> > + .subbuf_size = 4,
> > +};
> > +
> > +FIXTURE_VARIANT_ADD(map, subbuf_size_8k) {
> > + .subbuf_size = 8,
> > +};
> > +
> > +FIXTURE_SETUP(map)
> > +{
> > + int cpu = sched_getcpu(), page_size = getpagesize();
> > + unsigned long meta_len, data_len;
> > + char *cpu_path, *message;
> > + bool fail, umount;
> > + cpu_set_t cpu_mask;
> > + void *map;
> > +
> > + if (!tracefs_enabled(&message, &fail, &umount)) {
> > + if (fail) {
> > + TH_LOG("Tracefs setup failed: %s", message);
> > + ASSERT_FALSE(fail);
> > + }
> > + SKIP(return, "Skipping: %s", message);
> > + }
> > +
> > + self->umount = umount;
> > +
> > + ASSERT_GE(cpu, 0);
> > +
> > + ASSERT_EQ(tracefs_reset(), 0);
> > +
> > + tracefs_write_int(TRACEFS_ROOT"/buffer_subbuf_size_kb", variant->subbuf_size);
> > +
> > + ASSERT_GE(asprintf(&cpu_path,
> > + TRACEFS_ROOT"/per_cpu/cpu%d/trace_pipe_raw",
> > + cpu), 0);
> > +
> > + self->cpu_fd = open(cpu_path, O_RDONLY | O_NONBLOCK);
> > + ASSERT_GE(self->cpu_fd, 0);
> > + free(cpu_path);
> > +
> > + map = mmap(NULL, page_size, PROT_READ, MAP_SHARED, self->cpu_fd, 0);
> > + ASSERT_NE(map, MAP_FAILED);
> > + self->meta = (struct trace_buffer_meta *)map;
> > +
> > + meta_len = self->meta->meta_page_size;
> > + data_len = self->meta->subbuf_size * self->meta->nr_subbufs;
> > +
> > + map = mmap(NULL, data_len, PROT_READ, MAP_SHARED, self->cpu_fd, meta_len);
> > + ASSERT_NE(map, MAP_FAILED);
> > + self->data = map;
> > +
> > + /*
> > + * Ensure generated events will be found on this very same ring-buffer.
> > + */
> > + CPU_ZERO(&cpu_mask);
> > + CPU_SET(cpu, &cpu_mask);
> > + ASSERT_EQ(sched_setaffinity(0, sizeof(cpu_mask), &cpu_mask), 0);
> > +}
> > +
> > +FIXTURE_TEARDOWN(map)
> > +{
> > + tracefs_reset();
> > +
> > + if (self->umount)
> > + tracefs_unmount();
> > +
> > + munmap(self->data, self->meta->subbuf_size * self->meta->nr_subbufs);
> > + munmap(self->meta, self->meta->meta_page_size);
> > + close(self->cpu_fd);
> > +}
> > +
> > +TEST_F(map, meta_page_check)
> > +{
> > + int cnt = 0;
> > +
> > + ASSERT_EQ(self->meta->entries, 0);
> > + ASSERT_EQ(self->meta->overrun, 0);
> > + ASSERT_EQ(self->meta->read, 0);
> > + ASSERT_EQ(self->meta->subbufs_touched, 0);
> > + ASSERT_EQ(self->meta->subbufs_lost, 0);
> > + ASSERT_EQ(self->meta->subbufs_read, 0);
> > +
> > + ASSERT_EQ(self->meta->reader.id, 0);
> > + ASSERT_EQ(self->meta->reader.read, 0);
> > +
> > + ASSERT_EQ(ioctl(self->cpu_fd, TRACE_MMAP_IOCTL_GET_READER), 0);
> > + ASSERT_EQ(self->meta->reader.id, 0);
> > +
> > + tracefs_write_int(TRACEFS_ROOT"/tracing_on", 1);
> > + for (int i = 0; i < 16; i++)
> > + tracefs_write_int(TRACEFS_ROOT"/trace_marker", i);
> > +again:
> > + ASSERT_EQ(ioctl(self->cpu_fd, TRACE_MMAP_IOCTL_GET_READER), 0);
> > +
> > + ASSERT_EQ(self->meta->entries, 16);
> > + ASSERT_EQ(self->meta->overrun, 0);
> > + ASSERT_EQ(self->meta->read, 16);
> > + /* subbufs_touched doesn't take into account the commit page */
> > + ASSERT_EQ(self->meta->subbufs_touched, 0);
> > + ASSERT_EQ(self->meta->subbufs_lost, 0);
> > + ASSERT_EQ(self->meta->subbufs_read, 1);
> > +
> > + ASSERT_EQ(self->meta->reader.id, 1);
> > +
> > + if (!(cnt++))
> > + goto again;
> > +}
> > +
> > +TEST_HARNESS_MAIN
> > --
> > 2.43.0.275.g3460e3d667-goog
> >
>
>
> --
> Masami Hiramatsu (Google) <mhiramat@...nel.org>
--
Masami Hiramatsu (Google) <mhiramat@...nel.org>
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