[PATCH] perf test: Skip watchpoint tests if no watchpoints available

[PATCH] perf test: Skip watchpoint tests if no watchpoints available

[Naveen N. Rao]

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@linux.vnet.ibm.com>
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.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);
+	}
 
 	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
-- 
2.38.1

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

[Christophe Leroy]

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@linux.vnet.ibm.com>
> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.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

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

[Ian Rogers]

On Tue, Nov 22, 2022 at 11:19 AM Christophe Leroy
<christophe.leroy@csgroup.eu> wrote:
>
>
>
> 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@linux.vnet.ibm.com>
> > Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.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 ?

errno is very easily clobbered and not clearly set on success - ie,
it'd be better not to do that.

Acked-by: Ian Rogers <irogers@google.com>

Thanks,
Ian

> >
> >       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

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

[kajoljain]

On 11/21/22 15:57, Naveen N. Rao wrote:
> 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@linux.vnet.ibm.com>
> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
> ---

Patch looks fine to me. Also tested it in power9 box

Test result without this patch changes :
 23: Watchpoint  :
 23.1: Read Only Watchpoint    : FAILED!
 23.2: Write Only Watchpoint   : FAILED!
 23.3: Read / Write Watchpoint : FAILED!
 23.4: Modify Watchpoint       : FAILED!


Test result with patch changes:
 23: Watchpoint  :
 23.1: Read Only Watchpoint    : Skip (missing hardware support)
 23.2: Write Only Watchpoint   : Skip (missing hardware support)
 23.3: Read / Write Watchpoint : Skip (missing hardware support)
 23.4: Modify Watchpoint       : Skip (missing hardware support)


Reviewed-by: Kajol Jain<kjain@linux.ibm.com>
Tested-by: Kajol Jain<kjain@linux.ibm.com>

Thanks,
Kajol Jain

>  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);
> +	}
>  
>  	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

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

[Arnaldo Carvalho de Melo]

Em Tue, Nov 22, 2022 at 12:57:05PM -0800, Ian Rogers escreveu:
> On Tue, Nov 22, 2022 at 11:19 AM Christophe Leroy
> <christophe.leroy@csgroup.eu> wrote:
> >
> >
> >
> > 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@linux.vnet.ibm.com>
> > > Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.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 ?
> 
> errno is very easily clobbered and not clearly set on success - ie,
> it'd be better not to do that.
> 
> Acked-by: Ian Rogers <irogers@google.com>

Thanks, applied.

- Arnaldo