diff mbox series

tst: Provide test for getrusage

Message ID 20210315104223.32542-1-lukma@denx.de
State Superseded
Delegated to: Adhemerval Zanella Netto
Headers show
Series tst: Provide test for getrusage | expand

Commit Message

Lukasz Majewski March 15, 2021, 10:42 a.m. UTC
This commit adds test to check if getrusage provides correct time
accounting for some busy wait loop.

To be more specific - the time is measured in a loop by wrappers
from glibc's libsupport and checked if timeout has passed.

Afterwards, the data from struct rusage, namely ru_stime and ru_utime
is summed up and compared with time from busy waiting.
---
 sysdeps/unix/sysv/linux/Makefile        |  2 +-
 sysdeps/unix/sysv/linux/tst-getrusage.c | 55 +++++++++++++++++++++++++
 2 files changed, 56 insertions(+), 1 deletion(-)
 create mode 100644 sysdeps/unix/sysv/linux/tst-getrusage.c

Comments

Andreas Schwab March 15, 2021, 10:55 a.m. UTC | #1
On Mär 15 2021, Lukasz Majewski wrote:

> diff --git a/sysdeps/unix/sysv/linux/tst-getrusage.c b/sysdeps/unix/sysv/linux/tst-getrusage.c
> new file mode 100644
> index 0000000000..068becdadb
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/tst-getrusage.c
> @@ -0,0 +1,55 @@
> +/* Test for getrusage
> +   Copyright (C) 2021 Free Software Foundation, Inc.
> +   This file is part of the GNU C Library.
> +
> +   The GNU C Library is free software; you can redistribute it and/or
> +   modify it under the terms of the GNU Lesser General Public
> +   License as published by the Free Software Foundation; either
> +   version 2.1 of the License, or (at your option) any later version.
> +
> +   The GNU C Library is distributed in the hope that it will be useful,
> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> +   Lesser General Public License for more details.
> +
> +   You should have received a copy of the GNU Lesser General Public
> +   License along with the GNU C Library; if not, see
> +   <https://www.gnu.org/licenses/>.  */
> +
> +#include <time.h>
> +#include <sys/resource.h>
> +#include <support/check.h>
> +#include <support/timespec.h>
> +
> +#define TST_GETRUSAGE_TIMEOUT 1
> +
> +static int
> +do_test (void)
> +{
> +  struct timespec tv_then, tv_now, gru_u, gru_s, s, r;
> +  struct rusage ru;
> +  int ret;
> +
> +  tv_then = xclock_now (CLOCK_REALTIME);
> +  /* Busy wait for 1 second.  */
> +  do
> +  {
> +    tv_now = xclock_now (CLOCK_REALTIME);
> +    r = timespec_sub (tv_now, tv_then);
> +  } while ( r.tv_sec != TST_GETRUSAGE_TIMEOUT );

What happens if the process stalls for a second?

Andreas.
Lukasz Majewski March 15, 2021, 1:56 p.m. UTC | #2
Hi Andreas,

> On Mär 15 2021, Lukasz Majewski wrote:
> 
> > diff --git a/sysdeps/unix/sysv/linux/tst-getrusage.c
> > b/sysdeps/unix/sysv/linux/tst-getrusage.c new file mode 100644
> > index 0000000000..068becdadb
> > --- /dev/null
> > +++ b/sysdeps/unix/sysv/linux/tst-getrusage.c
> > @@ -0,0 +1,55 @@
> > +/* Test for getrusage
> > +   Copyright (C) 2021 Free Software Foundation, Inc.
> > +   This file is part of the GNU C Library.
> > +
> > +   The GNU C Library is free software; you can redistribute it
> > and/or
> > +   modify it under the terms of the GNU Lesser General Public
> > +   License as published by the Free Software Foundation; either
> > +   version 2.1 of the License, or (at your option) any later
> > version. +
> > +   The GNU C Library is distributed in the hope that it will be
> > useful,
> > +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> > +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> > GNU
> > +   Lesser General Public License for more details.
> > +
> > +   You should have received a copy of the GNU Lesser General Public
> > +   License along with the GNU C Library; if not, see
> > +   <https://www.gnu.org/licenses/>.  */
> > +
> > +#include <time.h>
> > +#include <sys/resource.h>
> > +#include <support/check.h>
> > +#include <support/timespec.h>
> > +
> > +#define TST_GETRUSAGE_TIMEOUT 1
> > +
> > +static int
> > +do_test (void)
> > +{
> > +  struct timespec tv_then, tv_now, gru_u, gru_s, s, r;
> > +  struct rusage ru;
> > +  int ret;
> > +
> > +  tv_then = xclock_now (CLOCK_REALTIME);
> > +  /* Busy wait for 1 second.  */
> > +  do
> > +  {
> > +    tv_now = xclock_now (CLOCK_REALTIME);
> > +    r = timespec_sub (tv_now, tv_then);
> > +  } while ( r.tv_sec != TST_GETRUSAGE_TIMEOUT );  
> 
> What happens if the process stalls for a second?

I think that the glibc's test infrastructure will kill it - the default
timeout is 2 seconds.

As a result the test will fail.

> 
> Andreas.
> 




Best regards,

Lukasz Majewski

--

DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-59 Fax: (+49)-8142-66989-80 Email: lukma@denx.de
Lukasz Majewski March 17, 2021, 4:04 p.m. UTC | #3
Hi Andreas,

> Hi Andreas,
> 
> > On Mär 15 2021, Lukasz Majewski wrote:
> >   
> > > diff --git a/sysdeps/unix/sysv/linux/tst-getrusage.c
> > > b/sysdeps/unix/sysv/linux/tst-getrusage.c new file mode 100644
> > > index 0000000000..068becdadb
> > > --- /dev/null
> > > +++ b/sysdeps/unix/sysv/linux/tst-getrusage.c
> > > @@ -0,0 +1,55 @@
> > > +/* Test for getrusage
> > > +   Copyright (C) 2021 Free Software Foundation, Inc.
> > > +   This file is part of the GNU C Library.
> > > +
> > > +   The GNU C Library is free software; you can redistribute it
> > > and/or
> > > +   modify it under the terms of the GNU Lesser General Public
> > > +   License as published by the Free Software Foundation; either
> > > +   version 2.1 of the License, or (at your option) any later
> > > version. +
> > > +   The GNU C Library is distributed in the hope that it will be
> > > useful,
> > > +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> > > +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> > > GNU
> > > +   Lesser General Public License for more details.
> > > +
> > > +   You should have received a copy of the GNU Lesser General
> > > Public
> > > +   License along with the GNU C Library; if not, see
> > > +   <https://www.gnu.org/licenses/>.  */
> > > +
> > > +#include <time.h>
> > > +#include <sys/resource.h>
> > > +#include <support/check.h>
> > > +#include <support/timespec.h>
> > > +
> > > +#define TST_GETRUSAGE_TIMEOUT 1
> > > +
> > > +static int
> > > +do_test (void)
> > > +{
> > > +  struct timespec tv_then, tv_now, gru_u, gru_s, s, r;
> > > +  struct rusage ru;
> > > +  int ret;
> > > +
> > > +  tv_then = xclock_now (CLOCK_REALTIME);
> > > +  /* Busy wait for 1 second.  */
> > > +  do
> > > +  {
> > > +    tv_now = xclock_now (CLOCK_REALTIME);
> > > +    r = timespec_sub (tv_now, tv_then);
> > > +  } while ( r.tv_sec != TST_GETRUSAGE_TIMEOUT );    
> > 
> > What happens if the process stalls for a second?  
> 
> I think that the glibc's test infrastructure will kill it - the
> default timeout is 2 seconds.
> 
> As a result the test will fail.

On the other hand - the proposed approach with busy waiting was the
natural one to check if accounting from getrusage is correct.

Maybe you (or anybody else from the community) have a better idea on how
to force the process to be "running" (active) for some time?

Maybe I could modify the C test code to perform following bash
operation:
cat /dev/urandom | gzip -9 > /dev/null

and replace /dev/urandom with some large (generated in place) file?
However, this would pose additional dependencies (gzip) on glibc test
suite.

> 
> > 
> > Andreas.
> >   
> 
> 
> 
> 
> Best regards,
> 
> Lukasz Majewski
> 
> --
> 
> DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
> HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
> Phone: (+49)-8142-66989-59 Fax: (+49)-8142-66989-80 Email:
> lukma@denx.de




Best regards,

Lukasz Majewski

--

DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-59 Fax: (+49)-8142-66989-80 Email: lukma@denx.de
Andreas Schwab March 17, 2021, 4:24 p.m. UTC | #4
On Mär 17 2021, Lukasz Majewski wrote:

> Maybe you (or anybody else from the community) have a better idea on how
> to force the process to be "running" (active) for some time?

You don't get real-time scheduling on Unix.  You always have to account
for a process stalling for an arbitrary amount of time.

Andreas.
Lukasz Majewski March 22, 2021, 11:29 a.m. UTC | #5
Hi Andreas,

> On Mär 17 2021, Lukasz Majewski wrote:
> 
> > Maybe you (or anybody else from the community) have a better idea
> > on how to force the process to be "running" (active) for some time?
> >  
> 
> You don't get real-time scheduling on Unix.  You always have to
> account for a process stalling for an arbitrary amount of time.
> 
> Andreas.
> 

I'm just looking for ideas on how to reliably test getrusage.
Do you have any ideas?


Best regards,

Lukasz Majewski

--

DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-59 Fax: (+49)-8142-66989-80 Email: lukma@denx.de
Adhemerval Zanella March 22, 2021, 7:47 p.m. UTC | #6
On 15/03/2021 07:42, Lukasz Majewski wrote:
> This commit adds test to check if getrusage provides correct time
> accounting for some busy wait loop.
> 
> To be more specific - the time is measured in a loop by wrappers
> from glibc's libsupport and checked if timeout has passed.
> 
> Afterwards, the data from struct rusage, namely ru_stime and ru_utime
> is summed up and compared with time from busy waiting.
> ---
>   sysdeps/unix/sysv/linux/Makefile        |  2 +-
>   sysdeps/unix/sysv/linux/tst-getrusage.c | 55 +++++++++++++++++++++++++
>   2 files changed, 56 insertions(+), 1 deletion(-)
>   create mode 100644 sysdeps/unix/sysv/linux/tst-getrusage.c
> 
> diff --git a/sysdeps/unix/sysv/linux/Makefile b/sysdeps/unix/sysv/linux/Makefile
> index 6a45ac820a..a93fa4ca50 100644
> --- a/sysdeps/unix/sysv/linux/Makefile
> +++ b/sysdeps/unix/sysv/linux/Makefile
> @@ -113,7 +113,7 @@ tests += tst-clone tst-clone2 tst-clone3 tst-fanotify tst-personality \
>   	 tst-tgkill tst-sysvsem-linux tst-sysvmsg-linux tst-sysvshm-linux \
>   	 tst-timerfd tst-ppoll tst-futimens tst-utime tst-utimes \
>   	 tst-clock_adjtime tst-adjtimex tst-ntp_adjtime tst-futimes \
> -	 tst-lutimes tst-ntp_gettime tst-ntp_gettimex
> +	 tst-lutimes tst-ntp_gettime tst-ntp_gettimex tst-getrusage
>   tests-internal += tst-ofdlocks-compat tst-sigcontext-get_pc
>   tests-time64 += \
>     tst-futimes-time64\
> diff --git a/sysdeps/unix/sysv/linux/tst-getrusage.c b/sysdeps/unix/sysv/linux/tst-getrusage.c
> new file mode 100644
> index 0000000000..068becdadb
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/tst-getrusage.c
> @@ -0,0 +1,55 @@
> +/* Test for getrusage
> +   Copyright (C) 2021 Free Software Foundation, Inc.
> +   This file is part of the GNU C Library.
> +
> +   The GNU C Library is free software; you can redistribute it and/or
> +   modify it under the terms of the GNU Lesser General Public
> +   License as published by the Free Software Foundation; either
> +   version 2.1 of the License, or (at your option) any later version.
> +
> +   The GNU C Library is distributed in the hope that it will be useful,
> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> +   Lesser General Public License for more details.
> +
> +   You should have received a copy of the GNU Lesser General Public
> +   License along with the GNU C Library; if not, see
> +   <https://www.gnu.org/licenses/>.  */
> +
> +#include <time.h>
> +#include <sys/resource.h>
> +#include <support/check.h>
> +#include <support/timespec.h>
> +
> +#define TST_GETRUSAGE_TIMEOUT 1
> +
> +static int
> +do_test (void)
> +{
> +  struct timespec tv_then, tv_now, gru_u, gru_s, s, r;
> +  struct rusage ru;
> +  int ret;
> +
> +  tv_then = xclock_now (CLOCK_REALTIME);
> +  /* Busy wait for 1 second.  */
> +  do
> +  {
> +    tv_now = xclock_now (CLOCK_REALTIME);
> +    r = timespec_sub (tv_now, tv_then);
> +  } while ( r.tv_sec != TST_GETRUSAGE_TIMEOUT );
> +
> +  ret = getrusage (RUSAGE_SELF, &ru);
> +  if (ret == -1)
> +    FAIL_EXIT1 ("getrusage failed: %m\n");
> +
> +  gru_u = make_timespec (ru.ru_utime.tv_sec, ru.ru_utime.tv_usec * 1000);
> +  gru_s = make_timespec (ru.ru_stime.tv_sec, ru.ru_stime.tv_usec * 1000);
> +  s = timespec_add (gru_u, gru_s);
> +
> +  TEST_COMPARE (support_timespec_check_in_range
> +                ((struct timespec) { 1, 0 }, s, 0.8, 1.2), 1);
> +
> +  return 0;
> +}
> +
> +#include <support/test-driver.c>
> 

Timer accounting tests are tricky to get right and prone to show a
lot of false positive failures and has bitten us in the past (check
04deeaa9ea74 and 9a29f1a2ae3d4b).

So I think we should be as simple as possible and take in consideration
that tests will run a timer shared machine so even with a busy wait the
result timer might not take in consideration the desirable timeout.

So for geturage (which afaik is also deprecated on future POSIX) I
more simpler tests would be to:

   1. Check for invalid 'who' (the EFAULT result from man-pages only
      trigger where syscall is issued directly, which is not always
      the case for glibc).

   2. Issue getusage and check if the ru_utime.tv_nsec and
      ru_stime.tv_nsec are within the microseconds range.

   3. Do some very short busy wait (10ms) and check if the
      ru_utime.tv_sec and ru_stime.tv_sec are equal or larger
      than the previous one.

Also, I think this tests should generic, so move to resource
folder.
diff mbox series

Patch

diff --git a/sysdeps/unix/sysv/linux/Makefile b/sysdeps/unix/sysv/linux/Makefile
index 6a45ac820a..a93fa4ca50 100644
--- a/sysdeps/unix/sysv/linux/Makefile
+++ b/sysdeps/unix/sysv/linux/Makefile
@@ -113,7 +113,7 @@  tests += tst-clone tst-clone2 tst-clone3 tst-fanotify tst-personality \
 	 tst-tgkill tst-sysvsem-linux tst-sysvmsg-linux tst-sysvshm-linux \
 	 tst-timerfd tst-ppoll tst-futimens tst-utime tst-utimes \
 	 tst-clock_adjtime tst-adjtimex tst-ntp_adjtime tst-futimes \
-	 tst-lutimes tst-ntp_gettime tst-ntp_gettimex
+	 tst-lutimes tst-ntp_gettime tst-ntp_gettimex tst-getrusage
 tests-internal += tst-ofdlocks-compat tst-sigcontext-get_pc
 tests-time64 += \
   tst-futimes-time64\
diff --git a/sysdeps/unix/sysv/linux/tst-getrusage.c b/sysdeps/unix/sysv/linux/tst-getrusage.c
new file mode 100644
index 0000000000..068becdadb
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/tst-getrusage.c
@@ -0,0 +1,55 @@ 
+/* Test for getrusage
+   Copyright (C) 2021 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <time.h>
+#include <sys/resource.h>
+#include <support/check.h>
+#include <support/timespec.h>
+
+#define TST_GETRUSAGE_TIMEOUT 1
+
+static int
+do_test (void)
+{
+  struct timespec tv_then, tv_now, gru_u, gru_s, s, r;
+  struct rusage ru;
+  int ret;
+
+  tv_then = xclock_now (CLOCK_REALTIME);
+  /* Busy wait for 1 second.  */
+  do
+  {
+    tv_now = xclock_now (CLOCK_REALTIME);
+    r = timespec_sub (tv_now, tv_then);
+  } while ( r.tv_sec != TST_GETRUSAGE_TIMEOUT );
+
+  ret = getrusage (RUSAGE_SELF, &ru);
+  if (ret == -1)
+    FAIL_EXIT1 ("getrusage failed: %m\n");
+
+  gru_u = make_timespec (ru.ru_utime.tv_sec, ru.ru_utime.tv_usec * 1000);
+  gru_s = make_timespec (ru.ru_stime.tv_sec, ru.ru_stime.tv_usec * 1000);
+  s = timespec_add (gru_u, gru_s);
+
+  TEST_COMPARE (support_timespec_check_in_range
+                ((struct timespec) { 1, 0 }, s, 0.8, 1.2), 1);
+
+  return 0;
+}
+
+#include <support/test-driver.c>