Commit 032db28e authored by Jiri Olsa's avatar Jiri Olsa Committed by Ingo Molnar
Browse files

perf tests: Add breakpoint accounting/modify test 



Adding test that:

  - detects the number of watch/break-points,
    skip test if any is missing
  - detects PERF_EVENT_IOC_MODIFY_ATTRIBUTES ioctl,
    skip test if it's missing
  - detects if watchpoints and breakpoints share
    same slots
  - create all possible watchpoints on cpu 0
  - change one of it to breakpoint
  - in case wp and bp do not share slots,
    we create another watchpoint to ensure
    the slot accounting is correct

Signed-off-by: default avatarJiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Hari Bathini <hbathini@linux.vnet.ibm.com>
Cc: Jin Yao <yao.jin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Milind Chabbi <chabbi.milind@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Oleg Nesterov <onestero@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Link: http://lkml.kernel.org/r/20180312134548.31532-9-jolsa@kernel.org


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 5f970521

tools/perf/tests/Build

+1 −0
Original line number Diff line number Diff line
@@ -20,6 +20,7 @@ perf-y += hists_cumulate.o 
perf-y += python-use.o

perf-y += bp_signal.o

perf-y += bp_signal_overflow.o

perf-y += bp_account.o

perf-y += task-exit.o

perf-y += sw-clock.o

perf-y += mmap-thread-lookup.o

tools/perf/tests/bp_account.c

0 → 100644
+195 −0
Original line number Diff line number Diff line 
/*

 * Powerpc needs __SANE_USERSPACE_TYPES__ before <linux/types.h> to select

 * 'int-ll64.h' and avoid compile warnings when printing __u64 with %llu.

 */

#define __SANE_USERSPACE_TYPES__



#include <stdlib.h>

#include <stdio.h>

#include <unistd.h>

#include <string.h>

#include <sys/ioctl.h>

#include <time.h>

#include <fcntl.h>

#include <signal.h>

#include <sys/mman.h>

#include <linux/compiler.h>

#include <linux/hw_breakpoint.h>

#include <sys/ioctl.h>



#include "tests.h"

#include "debug.h"

#include "perf.h"

#include "cloexec.h"



volatile long the_var;



static noinline int test_function(void)

{

	return 0;

}



static int __event(bool is_x, void *addr, struct perf_event_attr *attr)

{

	int fd;



	memset(attr, 0, sizeof(struct perf_event_attr));

	attr->type = PERF_TYPE_BREAKPOINT;

	attr->size = sizeof(struct perf_event_attr);



	attr->config = 0;

	attr->bp_type = is_x ? HW_BREAKPOINT_X : HW_BREAKPOINT_W;

	attr->bp_addr = (unsigned long) addr;

	attr->bp_len = sizeof(long);



	attr->sample_period = 1;

	attr->sample_type = PERF_SAMPLE_IP;



	attr->exclude_kernel = 1;

	attr->exclude_hv = 1;



	fd = sys_perf_event_open(attr, -1, 0, -1,

				 perf_event_open_cloexec_flag());

	if (fd < 0) {

		pr_debug("failed opening event %llx\n", attr->config);

		return TEST_FAIL;

	}



	return fd;

}



static int wp_event(void *addr, struct perf_event_attr *attr)

{

	return __event(false, addr, attr);

}



static int bp_event(void *addr, struct perf_event_attr *attr)

{

	return __event(true, addr, attr);

}



static int bp_accounting(int wp_cnt, int share)

{

	struct perf_event_attr attr, attr_mod, attr_new;

	int i, fd[wp_cnt], fd_wp, ret;



	for (i = 0; i < wp_cnt; i++) {

		fd[i] = wp_event((void *)&the_var, &attr);

		TEST_ASSERT_VAL("failed to create wp\n", fd[i] != -1);

		pr_debug("wp %d created\n", i);

	}



	attr_mod = attr;

	attr_mod.bp_type = HW_BREAKPOINT_X;

	attr_mod.bp_addr = (unsigned long) test_function;



	ret = ioctl(fd[0], PERF_EVENT_IOC_MODIFY_ATTRIBUTES, &attr_mod);

	TEST_ASSERT_VAL("failed to modify wp\n", ret == 0);



	pr_debug("wp 0 modified to bp\n");



	if (!share) {

		fd_wp = wp_event((void *)&the_var, &attr_new);

		TEST_ASSERT_VAL("failed to create max wp\n", fd_wp != -1);

		pr_debug("wp max created\n");

	}



	for (i = 0; i < wp_cnt; i++)

		close(fd[i]);



	return 0;

}



static int detect_cnt(bool is_x)

{

	struct perf_event_attr attr;

	void *addr = is_x ? test_function : (void *) &the_var;

	int fd[100], cnt = 0, i;



	while (1) {

		fd[cnt] = __event(is_x, addr, &attr);



		if (fd[cnt] < 0)

			break;



		if (cnt == 100) {

			pr_debug("way too many debug registers, fix the test\n");

			return 0;

		}



		cnt++;

	}



	for (i = 0; i < cnt; i++)

		close(fd[i]);



	return cnt;

}



static int detect_ioctl(void)

{

	struct perf_event_attr attr;

	int fd, ret = 1;



	fd = wp_event((void *) &the_var, &attr);

	if (fd > 0) {

		ret = ioctl(fd, PERF_EVENT_IOC_MODIFY_ATTRIBUTES, &attr);

		close(fd);

	}



	return ret ? 0 : 1;

}



static int detect_share(int wp_cnt, int bp_cnt)

{

	struct perf_event_attr attr;

	int i, fd[wp_cnt + bp_cnt], ret;



	for (i = 0; i < wp_cnt; i++) {

		fd[i] = wp_event((void *)&the_var, &attr);

		TEST_ASSERT_VAL("failed to create wp\n", fd[i] != -1);

	}



	for (; i < (bp_cnt + wp_cnt); i++) {

		fd[i] = bp_event((void *)test_function, &attr);

		if (fd[i] == -1)

			break;

	}



	ret = i != (bp_cnt + wp_cnt);



	while (i--)

		close(fd[i]);



	return ret;

}



/*

 * This test does following:

 *   - detects the number of watch/break-points,

 *     skip test if any is missing

 *   - detects PERF_EVENT_IOC_MODIFY_ATTRIBUTES ioctl,

 *     skip test if it's missing

 *   - detects if watchpoints and breakpoints share

 *     same slots

 *   - create all possible watchpoints on cpu 0

 *   - change one of it to breakpoint

 *   - in case wp and bp do not share slots,

 *     we create another watchpoint to ensure

 *     the slot accounting is correct

 */

int test__bp_accounting(struct test *test __maybe_unused, int subtest __maybe_unused)

{

	int has_ioctl = detect_ioctl();

	int wp_cnt = detect_cnt(false);

	int bp_cnt = detect_cnt(true);

	int share  = detect_share(wp_cnt, bp_cnt);



	pr_debug("watchpoints count %d, breakpoints count %d, has_ioctl %d, share %d\n",

		 wp_cnt, bp_cnt, has_ioctl, share);



	if (!wp_cnt || !bp_cnt || !has_ioctl)

		return TEST_SKIP;



	return bp_accounting(wp_cnt, share);

}

tools/perf/tests/builtin-test.c

+4 −0
Original line number Diff line number Diff line
@@ -115,6 +115,10 @@ static struct test generic_tests[] = { 
		.func = test__bp_signal_overflow,

		.is_supported = test__bp_signal_is_supported,

	},

	{

		.desc = "Breakpoint accounting",

		.func = test__bp_accounting,

	},

	{

		.desc = "Number of exit events of a simple workload",

		.func = test__task_exit,

tools/perf/tests/tests.h

+1 −0
Original line number Diff line number Diff line
@@ -58,6 +58,7 @@ int test__hists_link(struct test *test, int subtest); 
int test__python_use(struct test *test, int subtest);

int test__bp_signal(struct test *test, int subtest);

int test__bp_signal_overflow(struct test *test, int subtest);

int test__bp_accounting(struct test *test, int subtest);

int test__task_exit(struct test *test, int subtest);

int test__mem(struct test *test, int subtest);

int test__sw_clock_freq(struct test *test, int subtest);

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