[v4] tracing: Support poll on event hist file

[PATCH v4 3/3] selftests/tracing: Add hist poll() support test

Posted by Masami Hiramatsu (Google) 1 year, 5 months ago

From: Masami Hiramatsu (Google) <mhiramat@kernel.org>

Add a testcase for poll() on hist file. This introduces a helper binary
to the ftracetest, because there is no good way to reliably execute
poll() on hist file.

Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
---
 Changes in v4:
  - Use getopt() in poll.c (command options are changed)
  - Update test code according to the new command options.
 Changes in v2:
  - Update poll command to support both of POLLIN and POLLPRI, and timeout.
  - Identify unsupported stable kernel if poll-in returns soon.
  - Test both of POLLIN and POLLPRI.
---
 tools/testing/selftests/ftrace/Makefile            |    2 +
 tools/testing/selftests/ftrace/poll.c              |   74 ++++++++++++++++++++
 .../ftrace/test.d/trigger/trigger-hist-poll.tc     |   74 ++++++++++++++++++++
 3 files changed, 150 insertions(+)
 create mode 100644 tools/testing/selftests/ftrace/poll.c
 create mode 100644 tools/testing/selftests/ftrace/test.d/trigger/trigger-hist-poll.tc

diff --git a/tools/testing/selftests/ftrace/Makefile b/tools/testing/selftests/ftrace/Makefile
index a1e955d2de4c..49d96bb16355 100644
--- a/tools/testing/selftests/ftrace/Makefile
+++ b/tools/testing/selftests/ftrace/Makefile
@@ -6,4 +6,6 @@ TEST_PROGS := ftracetest-ktap
 TEST_FILES := test.d settings
 EXTRA_CLEAN := $(OUTPUT)/logs/*
 
+TEST_GEN_PROGS = poll
+
 include ../lib.mk
diff --git a/tools/testing/selftests/ftrace/poll.c b/tools/testing/selftests/ftrace/poll.c
new file mode 100644
index 000000000000..584f159654b1
--- /dev/null
+++ b/tools/testing/selftests/ftrace/poll.c
@@ -0,0 +1,74 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Simple poll on a file.
+ *
+ * Copyright (c) 2024 Google LLC.
+ */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <poll.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#define BUFSIZE 4096
+
+/*
+ * Usage:
+ *  poll [-I|-P] [-t timeout] FILE
+ */
+int main(int argc, char *argv[])
+{
+	struct pollfd pfd = {.events = POLLIN};
+	char buf[BUFSIZE];
+	int timeout = -1;
+	int ret, opt;
+
+	while ((opt = getopt(argc, argv, "IPt:")) != -1) {
+		switch (opt) {
+		case 'I':
+			pfd.events = POLLIN;
+			break;
+		case 'P':
+			pfd.events = POLLPRI;
+			break;
+		case 't':
+			timeout = atoi(optarg);
+			break;
+		default:
+			fprintf(stderr, "Usage: %s [-I|-P] [-t timeout] FILE\n",
+				argv[0]);
+			return -1;
+		}
+	}
+	if (optind >= argc) {
+		fprintf(stderr, "Error: Polling file is not specified\n");
+		return -1;
+	}
+
+	pfd.fd = open(argv[optind], O_RDONLY);
+	if (pfd.fd < 0) {
+		fprintf(stderr, "failed to open %s", argv[optind]);
+		perror("open");
+		return -1;
+	}
+
+	/* Reset poll by read if POLLIN is specified. */
+	if (pfd.events & POLLIN)
+		do {} while (read(pfd.fd, buf, BUFSIZE) == BUFSIZE);
+
+	ret = poll(&pfd, 1, timeout);
+	if (ret < 0 && errno != EINTR) {
+		perror("poll");
+		return -1;
+	}
+	close(pfd.fd);
+
+	/* If timeout happned, return code is 0 */
+	if (ret == 0)
+		return 1;
+
+	return 0;
+}
diff --git a/tools/testing/selftests/ftrace/test.d/trigger/trigger-hist-poll.tc b/tools/testing/selftests/ftrace/test.d/trigger/trigger-hist-poll.tc
new file mode 100644
index 000000000000..cbd01a71ecad
--- /dev/null
+++ b/tools/testing/selftests/ftrace/test.d/trigger/trigger-hist-poll.tc
@@ -0,0 +1,74 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# description: event trigger - test poll wait on histogram
+# requires: set_event events/sched/sched_process_free/trigger events/sched/sched_process_free/hist
+# flags: instance
+
+POLL=${FTRACETEST_ROOT}/poll
+
+if [ ! -x ${POLL} ]; then
+  echo "poll program is not compiled!"
+  exit_unresolved
+fi
+
+EVENT=events/sched/sched_process_free/
+
+# Check poll ops is supported. Before implementing poll on hist file, it
+# returns soon with POLLIN | POLLOUT, but not POLLPRI.
+
+# This must wait >1 sec and return 1 (timeout).
+set +e
+${POLL} -I -t 1000 ${EVENT}/hist
+ret=$?
+set -e
+if [ ${ret} != 1 ]; then
+  echo "poll on hist file is not supported"
+  exit_unsupported
+fi
+
+# Test POLLIN
+echo > trace
+echo "hist:key=comm" > ${EVENT}/trigger
+echo 1 > ${EVENT}/enable
+
+# This sleep command will exit after 2 seconds.
+sleep 2 &
+BGPID=$!
+# if timeout happens, poll returns 1.
+${POLL} -I -t 4000 ${EVENT}/hist
+echo 0 > tracing_on
+
+if [ -d /proc/${BGPID} ]; then
+  echo "poll exits too soon"
+  kill -KILL ${BGPID} ||:
+  exit_fail
+fi
+
+if ! grep -qw "sleep" trace; then
+  echo "poll exits before event happens"
+  exit_fail
+fi
+
+# Test POLLPRI
+echo > trace
+echo 1 > tracing_on
+
+# This sleep command will exit after 2 seconds.
+sleep 2 &
+BGPID=$!
+# if timeout happens, poll returns 1.
+${POLL} -P -t 4000 ${EVENT}/hist
+echo 0 > tracing_on
+
+if [ -d /proc/${BGPID} ]; then
+  echo "poll exits too soon"
+  kill -KILL ${BGPID} ||:
+  exit_fail
+fi
+
+if ! grep -qw "sleep" trace; then
+  echo "poll exits before event happens"
+  exit_fail
+fi
+
+exit_pass

Re: [PATCH v4 3/3] selftests/tracing: Add hist poll() support test

Posted by Shuah Khan 1 year, 5 months ago

On 8/15/24 20:31, Masami Hiramatsu (Google) wrote:
> From: Masami Hiramatsu (Google) <mhiramat@kernel.org>
> 
> Add a testcase for poll() on hist file. This introduces a helper binary
> to the ftracetest, because there is no good way to reliably execute
> poll() on hist file.
> 
> Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
> ---
>   Changes in v4:
>    - Use getopt() in poll.c (command options are changed)
>    - Update test code according to the new command options.
>   Changes in v2:
>    - Update poll command to support both of POLLIN and POLLPRI, and timeout.
>    - Identify unsupported stable kernel if poll-in returns soon.
>    - Test both of POLLIN and POLLPRI.
> ---
>   tools/testing/selftests/ftrace/Makefile            |    2 +
>   tools/testing/selftests/ftrace/poll.c              |   74 ++++++++++++++++++++
>   .../ftrace/test.d/trigger/trigger-hist-poll.tc     |   74 ++++++++++++++++++++
>   3 files changed, 150 insertions(+)
>   create mode 100644 tools/testing/selftests/ftrace/poll.c
>   create mode 100644 tools/testing/selftests/ftrace/test.d/trigger/trigger-hist-poll.tc
> 
> diff --git a/tools/testing/selftests/ftrace/Makefile b/tools/testing/selftests/ftrace/Makefile
> index a1e955d2de4c..49d96bb16355 100644
> --- a/tools/testing/selftests/ftrace/Makefile
> +++ b/tools/testing/selftests/ftrace/Makefile
> @@ -6,4 +6,6 @@ TEST_PROGS := ftracetest-ktap
>   TEST_FILES := test.d settings
>   EXTRA_CLEAN := $(OUTPUT)/logs/*
>   
> +TEST_GEN_PROGS = poll
> +
>   include ../lib.mk
> diff --git a/tools/testing/selftests/ftrace/poll.c b/tools/testing/selftests/ftrace/poll.c
> new file mode 100644
> index 000000000000..584f159654b1
> --- /dev/null
> +++ b/tools/testing/selftests/ftrace/poll.c
> @@ -0,0 +1,74 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Simple poll on a file.
> + *
> + * Copyright (c) 2024 Google LLC.
> + */
> +
> +#include <errno.h>
> +#include <fcntl.h>
> +#include <poll.h>
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <string.h>
> +#include <unistd.h>
> +
> +#define BUFSIZE 4096
> +
> +/*
> + * Usage:
> + *  poll [-I|-P] [-t timeout] FILE
> + */
> +int main(int argc, char *argv[])
> +{
> +	struct pollfd pfd = {.events = POLLIN};
> +	char buf[BUFSIZE];
> +	int timeout = -1;
> +	int ret, opt;
> +
> +	while ((opt = getopt(argc, argv, "IPt:")) != -1) {
> +		switch (opt) {
> +		case 'I':
> +			pfd.events = POLLIN;
> +			break;
> +		case 'P':
> +			pfd.events = POLLPRI;
> +			break;
> +		case 't':
> +			timeout = atoi(optarg);
> +			break;
> +		default:
> +			fprintf(stderr, "Usage: %s [-I|-P] [-t timeout] FILE\n",
> +				argv[0]);
> +			return -1;
> +		}
> +	}
> +	if (optind >= argc) {
> +		fprintf(stderr, "Error: Polling file is not specified\n");
> +		return -1;
> +	}
> +
> +	pfd.fd = open(argv[optind], O_RDONLY);
> +	if (pfd.fd < 0) {
> +		fprintf(stderr, "failed to open %s", argv[optind]);
> +		perror("open");
> +		return -1;
> +	}
> +
> +	/* Reset poll by read if POLLIN is specified. */
> +	if (pfd.events & POLLIN)
> +		do {} while (read(pfd.fd, buf, BUFSIZE) == BUFSIZE);
> +
> +	ret = poll(&pfd, 1, timeout);
> +	if (ret < 0 && errno != EINTR) {
> +		perror("poll");
> +		return -1;
> +	}
> +	close(pfd.fd);
> +
> +	/* If timeout happned, return code is 0 */

Looks like you missed this one :) Otherwise looks good to me.

With this fixed

Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>

thanks,
-- Shuah

Re: [PATCH v4 3/3] selftests/tracing: Add hist poll() support test

Posted by Masami Hiramatsu (Google) 1 year, 5 months ago

On Fri, 16 Aug 2024 08:04:41 -0600
Shuah Khan <skhan@linuxfoundation.org> wrote:

> On 8/15/24 20:31, Masami Hiramatsu (Google) wrote:
> > From: Masami Hiramatsu (Google) <mhiramat@kernel.org>
> > 
> > Add a testcase for poll() on hist file. This introduces a helper binary
> > to the ftracetest, because there is no good way to reliably execute
> > poll() on hist file.
> > 
> > Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
> > ---
> >   Changes in v4:
> >    - Use getopt() in poll.c (command options are changed)
> >    - Update test code according to the new command options.
> >   Changes in v2:
> >    - Update poll command to support both of POLLIN and POLLPRI, and timeout.
> >    - Identify unsupported stable kernel if poll-in returns soon.
> >    - Test both of POLLIN and POLLPRI.
> > ---
> >   tools/testing/selftests/ftrace/Makefile            |    2 +
> >   tools/testing/selftests/ftrace/poll.c              |   74 ++++++++++++++++++++
> >   .../ftrace/test.d/trigger/trigger-hist-poll.tc     |   74 ++++++++++++++++++++
> >   3 files changed, 150 insertions(+)
> >   create mode 100644 tools/testing/selftests/ftrace/poll.c
> >   create mode 100644 tools/testing/selftests/ftrace/test.d/trigger/trigger-hist-poll.tc
> > 
> > diff --git a/tools/testing/selftests/ftrace/Makefile b/tools/testing/selftests/ftrace/Makefile
> > index a1e955d2de4c..49d96bb16355 100644
> > --- a/tools/testing/selftests/ftrace/Makefile
> > +++ b/tools/testing/selftests/ftrace/Makefile
> > @@ -6,4 +6,6 @@ TEST_PROGS := ftracetest-ktap
> >   TEST_FILES := test.d settings
> >   EXTRA_CLEAN := $(OUTPUT)/logs/*
> >   
> > +TEST_GEN_PROGS = poll
> > +
> >   include ../lib.mk
> > diff --git a/tools/testing/selftests/ftrace/poll.c b/tools/testing/selftests/ftrace/poll.c
> > new file mode 100644
> > index 000000000000..584f159654b1
> > --- /dev/null
> > +++ b/tools/testing/selftests/ftrace/poll.c
> > @@ -0,0 +1,74 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Simple poll on a file.
> > + *
> > + * Copyright (c) 2024 Google LLC.
> > + */
> > +
> > +#include <errno.h>
> > +#include <fcntl.h>
> > +#include <poll.h>
> > +#include <stdio.h>
> > +#include <stdlib.h>
> > +#include <string.h>
> > +#include <unistd.h>
> > +
> > +#define BUFSIZE 4096
> > +
> > +/*
> > + * Usage:
> > + *  poll [-I|-P] [-t timeout] FILE
> > + */
> > +int main(int argc, char *argv[])
> > +{
> > +	struct pollfd pfd = {.events = POLLIN};
> > +	char buf[BUFSIZE];
> > +	int timeout = -1;
> > +	int ret, opt;
> > +
> > +	while ((opt = getopt(argc, argv, "IPt:")) != -1) {
> > +		switch (opt) {
> > +		case 'I':
> > +			pfd.events = POLLIN;
> > +			break;
> > +		case 'P':
> > +			pfd.events = POLLPRI;
> > +			break;
> > +		case 't':
> > +			timeout = atoi(optarg);
> > +			break;
> > +		default:
> > +			fprintf(stderr, "Usage: %s [-I|-P] [-t timeout] FILE\n",
> > +				argv[0]);
> > +			return -1;
> > +		}
> > +	}
> > +	if (optind >= argc) {
> > +		fprintf(stderr, "Error: Polling file is not specified\n");
> > +		return -1;
> > +	}
> > +
> > +	pfd.fd = open(argv[optind], O_RDONLY);
> > +	if (pfd.fd < 0) {
> > +		fprintf(stderr, "failed to open %s", argv[optind]);
> > +		perror("open");
> > +		return -1;
> > +	}
> > +
> > +	/* Reset poll by read if POLLIN is specified. */
> > +	if (pfd.events & POLLIN)
> > +		do {} while (read(pfd.fd, buf, BUFSIZE) == BUFSIZE);
> > +
> > +	ret = poll(&pfd, 1, timeout);
> > +	if (ret < 0 && errno != EINTR) {
> > +		perror("poll");
> > +		return -1;
> > +	}
> > +	close(pfd.fd);
> > +
> > +	/* If timeout happned, return code is 0 */
> 
> Looks like you missed this one :) Otherwise looks good to me.
> 
Oops, indeed.

> With this fixed
> 
> Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>

Thanks!

> 
> thanks,
> -- Shuah


-- 
Masami Hiramatsu (Google) <mhiramat@kernel.org>

Re: [PATCH v4 3/3] selftests/tracing: Add hist poll() support test

Posted by Masami Hiramatsu (Google) 1 year, 5 months ago

On Sun, 18 Aug 2024 00:06:20 +0900
Masami Hiramatsu (Google) <mhiramat@kernel.org> wrote:

> On Fri, 16 Aug 2024 08:04:41 -0600
> Shuah Khan <skhan@linuxfoundation.org> wrote:
> 
> > On 8/15/24 20:31, Masami Hiramatsu (Google) wrote:
> > > From: Masami Hiramatsu (Google) <mhiramat@kernel.org>
> > > 
> > > Add a testcase for poll() on hist file. This introduces a helper binary
> > > to the ftracetest, because there is no good way to reliably execute
> > > poll() on hist file.
> > > 
> > > Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
> > > ---
> > >   Changes in v4:
> > >    - Use getopt() in poll.c (command options are changed)
> > >    - Update test code according to the new command options.
> > >   Changes in v2:
> > >    - Update poll command to support both of POLLIN and POLLPRI, and timeout.
> > >    - Identify unsupported stable kernel if poll-in returns soon.
> > >    - Test both of POLLIN and POLLPRI.
> > > ---
> > >   tools/testing/selftests/ftrace/Makefile            |    2 +
> > >   tools/testing/selftests/ftrace/poll.c              |   74 ++++++++++++++++++++
> > >   .../ftrace/test.d/trigger/trigger-hist-poll.tc     |   74 ++++++++++++++++++++
> > >   3 files changed, 150 insertions(+)
> > >   create mode 100644 tools/testing/selftests/ftrace/poll.c
> > >   create mode 100644 tools/testing/selftests/ftrace/test.d/trigger/trigger-hist-poll.tc
> > > 
> > > diff --git a/tools/testing/selftests/ftrace/Makefile b/tools/testing/selftests/ftrace/Makefile
> > > index a1e955d2de4c..49d96bb16355 100644
> > > --- a/tools/testing/selftests/ftrace/Makefile
> > > +++ b/tools/testing/selftests/ftrace/Makefile
> > > @@ -6,4 +6,6 @@ TEST_PROGS := ftracetest-ktap
> > >   TEST_FILES := test.d settings
> > >   EXTRA_CLEAN := $(OUTPUT)/logs/*
> > >   
> > > +TEST_GEN_PROGS = poll
> > > +
> > >   include ../lib.mk
> > > diff --git a/tools/testing/selftests/ftrace/poll.c b/tools/testing/selftests/ftrace/poll.c
> > > new file mode 100644
> > > index 000000000000..584f159654b1
> > > --- /dev/null
> > > +++ b/tools/testing/selftests/ftrace/poll.c
> > > @@ -0,0 +1,74 @@
> > > +// SPDX-License-Identifier: GPL-2.0
> > > +/*
> > > + * Simple poll on a file.
> > > + *
> > > + * Copyright (c) 2024 Google LLC.
> > > + */
> > > +
> > > +#include <errno.h>
> > > +#include <fcntl.h>
> > > +#include <poll.h>
> > > +#include <stdio.h>
> > > +#include <stdlib.h>
> > > +#include <string.h>
> > > +#include <unistd.h>
> > > +
> > > +#define BUFSIZE 4096
> > > +
> > > +/*
> > > + * Usage:
> > > + *  poll [-I|-P] [-t timeout] FILE
> > > + */
> > > +int main(int argc, char *argv[])
> > > +{
> > > +	struct pollfd pfd = {.events = POLLIN};
> > > +	char buf[BUFSIZE];
> > > +	int timeout = -1;
> > > +	int ret, opt;
> > > +
> > > +	while ((opt = getopt(argc, argv, "IPt:")) != -1) {
> > > +		switch (opt) {
> > > +		case 'I':
> > > +			pfd.events = POLLIN;
> > > +			break;
> > > +		case 'P':
> > > +			pfd.events = POLLPRI;
> > > +			break;
> > > +		case 't':
> > > +			timeout = atoi(optarg);
> > > +			break;
> > > +		default:
> > > +			fprintf(stderr, "Usage: %s [-I|-P] [-t timeout] FILE\n",
> > > +				argv[0]);
> > > +			return -1;
> > > +		}
> > > +	}
> > > +	if (optind >= argc) {
> > > +		fprintf(stderr, "Error: Polling file is not specified\n");
> > > +		return -1;
> > > +	}
> > > +
> > > +	pfd.fd = open(argv[optind], O_RDONLY);
> > > +	if (pfd.fd < 0) {
> > > +		fprintf(stderr, "failed to open %s", argv[optind]);
> > > +		perror("open");
> > > +		return -1;
> > > +	}
> > > +
> > > +	/* Reset poll by read if POLLIN is specified. */
> > > +	if (pfd.events & POLLIN)
> > > +		do {} while (read(pfd.fd, buf, BUFSIZE) == BUFSIZE);
> > > +
> > > +	ret = poll(&pfd, 1, timeout);
> > > +	if (ret < 0 && errno != EINTR) {
> > > +		perror("poll");
> > > +		return -1;
> > > +	}
> > > +	close(pfd.fd);
> > > +
> > > +	/* If timeout happned, return code is 0 */
> > 
> > Looks like you missed this one :) Otherwise looks good to me.
> > 
> Oops, indeed.

Hm, this comment is correct but misleadable. I meant that the poll()
returns 0 if timeout happens.

-----
RETURN VALUE
       On success, poll() returns a nonnegative value which is the  number  of  elements  in  the
       pollfds  whose  revents fields have been set to a nonzero value (indicating an event or an
       error).  A return value of zero indicates that the system call timed out before  any  file
       descriptors became read.
-----

But the comment should tell what this command does.

Thanks,

> 
> > With this fixed
> > 
> > Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>
> 
> Thanks!
> 
> > 
> > thanks,
> > -- Shuah
> 
> 
> -- 
> Masami Hiramatsu (Google) <mhiramat@kernel.org>


-- 
Masami Hiramatsu (Google) <mhiramat@kernel.org>

[PATCH v4 1/3] tracing/hist: Add poll(POLLIN) support on hist file
[PATCH v4 2/3] tracing/hist: Support POLLPRI event for poll on histogram
[PATCH v4 3/3] selftests/tracing: Add hist poll() support test