linux-kernel - Re: [PATCH] perf test: Skip watchpoint tests if no watchpoints available

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Message-ID: <a9f0f8f1-96cd-f6a8-9dda-d4744b938f97@csgroup.eu>
Date:   Tue, 22 Nov 2022 19:18:36 +0000
From:   Christophe Leroy <christophe.leroy@...roup.eu>
To:     "Naveen N. Rao" <naveen.n.rao@...ux.vnet.ibm.com>,
        Arnaldo Carvalho de Melo <acme@...nel.org>
CC:     Ravi Bangoria <ravi.bangoria@....com>,
        "linux-perf-users@...r.kernel.org" <linux-perf-users@...r.kernel.org>,
        Disha Goel <disgoel@...ux.vnet.ibm.com>,
        "linuxppc-dev@...ts.ozlabs.org" <linuxppc-dev@...ts.ozlabs.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] perf test: Skip watchpoint tests if no watchpoints
 available



Le 21/11/2022 à 11:27, Naveen N. Rao a écrit :
> On IBM Power9, perf watchpoint tests fail since no hardware breakpoints
> are available. Detect this by checking the error returned by
> perf_event_open() and skip the tests in that case.
> 
> Reported-by: Disha Goel <disgoel@...ux.vnet.ibm.com>
> Signed-off-by: Naveen N. Rao <naveen.n.rao@...ux.vnet.ibm.com>
> ---
>   tools/perf/tests/wp.c | 12 +++++++-----
>   1 file changed, 7 insertions(+), 5 deletions(-)
> 
> diff --git a/tools/perf/tests/wp.c b/tools/perf/tests/wp.c
> index 56455da30341b4..cc8719609b19ea 100644
> --- a/tools/perf/tests/wp.c
> +++ b/tools/perf/tests/wp.c
> @@ -59,8 +59,10 @@ static int __event(int wp_type, void *wp_addr, unsigned long wp_len)
>   	get__perf_event_attr(&attr, wp_type, wp_addr, wp_len);
>   	fd = sys_perf_event_open(&attr, 0, -1, -1,
>   				 perf_event_open_cloexec_flag());
> -	if (fd < 0)
> +	if (fd < 0) {
> +		fd = -errno;
>   		pr_debug("failed opening event %x\n", attr.bp_type);
> +	}

Do you really need that ?

Can't you directly check errno in the caller ?

>   
>   	return fd;
>   }
> @@ -77,7 +79,7 @@ static int test__wp_ro(struct test_suite *test __maybe_unused,
>   
>   	fd = __event(HW_BREAKPOINT_R, (void *)&data1, sizeof(data1));
>   	if (fd < 0)
> -		return -1;
> +		return fd == -ENODEV ? TEST_SKIP : -1;
>   
>   	tmp = data1;
>   	WP_TEST_ASSERT_VAL(fd, "RO watchpoint", 1);
> @@ -101,7 +103,7 @@ static int test__wp_wo(struct test_suite *test __maybe_unused,
>   
>   	fd = __event(HW_BREAKPOINT_W, (void *)&data1, sizeof(data1));
>   	if (fd < 0)
> -		return -1;
> +		return fd == -ENODEV ? TEST_SKIP : -1;
>   
>   	tmp = data1;
>   	WP_TEST_ASSERT_VAL(fd, "WO watchpoint", 0);
> @@ -126,7 +128,7 @@ static int test__wp_rw(struct test_suite *test __maybe_unused,
>   	fd = __event(HW_BREAKPOINT_R | HW_BREAKPOINT_W, (void *)&data1,
>   		     sizeof(data1));
>   	if (fd < 0)
> -		return -1;
> +		return fd == -ENODEV ? TEST_SKIP : -1;
>   
>   	tmp = data1;
>   	WP_TEST_ASSERT_VAL(fd, "RW watchpoint", 1);
> @@ -150,7 +152,7 @@ static int test__wp_modify(struct test_suite *test __maybe_unused, int subtest _
>   
>   	fd = __event(HW_BREAKPOINT_W, (void *)&data1, sizeof(data1));
>   	if (fd < 0)
> -		return -1;
> +		return fd == -ENODEV ? TEST_SKIP : -1;
>   
>   	data1 = tmp;
>   	WP_TEST_ASSERT_VAL(fd, "Modify watchpoint", 1);
> 
> base-commit: 63a3bf5e8d9e79ce456c8f73d4395a5a51d841b1