[Bug time/28071] New: clock_gettime lost vDSO acceleration on older kernels

[Bug time/28071] New: clock_gettime lost vDSO acceleration on older kernels

[fweimer at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=28071

            Bug ID: 28071
           Summary: clock_gettime lost vDSO acceleration on older kernels
           Product: glibc
           Version: 2.34
            Status: NEW
          Severity: normal
          Priority: P2
         Component: time
          Assignee: unassigned at sourceware dot org
          Reporter: fweimer at redhat dot com
  Target Milestone: ---

#include <time.h>
#include <stdio.h>
#include <errno.h>

int
main (void)
{
  struct timespec ts;
  errno = 0;
  clock_gettime (CLOCK_MONOTONIC, &ts);
  printf ("errno = %m (%d)\n", errno);
  errno = 0;
  clock_gettime (CLOCK_MONOTONIC, &ts);
  printf ("errno = %m (%d)\n", errno);
}

strace shows:

[…]
munmap(0xf7f5b000, 11321)               = 0
clock_gettime64(CLOCK_MONOTONIC, 0xffb785dc) = -1 ENOSYS (Function not
implemented)
statx(1, "", AT_STATX_SYNC_AS_STAT|AT_NO_AUTOMOUNT|AT_EMPTY_PATH,
STATX_BASIC_STATS, {stx_mask=STATX_BASIC_STATS, stx_attributes=0,
stx_mode=S_IFCHR|0620, stx_size=0, ...}) = 0
brk(NULL)                               = 0x9388000
brk(0x93a9000)                          = 0x93a9000
brk(0x93aa000)                          = 0x93aa000
write(1, "errno = Function not implemented"..., 38errno = Function not
implemented (38)
) = 38
clock_gettime64(CLOCK_MONOTONIC, 0xffb785dc) = -1 ENOSYS (Function not
implemented)
write(1, "errno = Function not implemented"..., 38errno = Function not
implemented (38)
) = 38
exit_group(0)                           = ?
+++ exited with 0 +++

Clobbering

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[Bug time/28071] clock_gettime lost vDSO acceleration on older kernels

[fweimer at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=28071

Florian Weimer <fweimer at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |fweimer at redhat dot com
           See Also|                            |https://bugs.openjdk.java.n
                   |                            |et/browse/JDK-8270244

--- Comment #1 from Florian Weimer <fweimer at redhat dot com> ---
Clobbering errno is also undesirable because it exposes application bugs.

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[Bug time/28071] clock_gettime lost vDSO acceleration on older kernels

[fweimer at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=28071

Florian Weimer <fweimer at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Target|                            |i686-linux-gnu

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[Bug time/28071] clock_gettime, gettimeofday, time lost vDSO acceleration on older kernels

[fweimer at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=28071

Florian Weimer <fweimer at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|clock_gettime lost vDSO     |clock_gettime,
                   |acceleration on older       |gettimeofday, time lost
                   |kernels                     |vDSO acceleration on older
                   |                            |kernels

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[Bug time/28071] clock_gettime, gettimeofday, time lost vDSO acceleration on older kernels

[fweimer at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=28071

Florian Weimer <fweimer at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|unassigned at sourceware dot org   |fweimer at redhat dot com

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[Bug time/28071] clock_gettime, gettimeofday, time lost vDSO acceleration on older kernels

[fweimer at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=28071

Florian Weimer <fweimer at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED

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[Bug time/28071] clock_gettime, gettimeofday, time lost vDSO acceleration on older kernels

[fweimer at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=28071

--- Comment #2 from Florian Weimer <fweimer at redhat dot com> ---
Patch posted: https://sourceware.org/pipermail/libc-alpha/2021-July/128902.html

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[Bug time/28071] clock_gettime, gettimeofday, time lost vDSO acceleration on older kernels

[fweimer at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=28071

Florian Weimer <fweimer at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           See Also|                            |https://bugzilla.redhat.com
                   |                            |/show_bug.cgi?id=1981013

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[Bug time/28071] clock_gettime, gettimeofday, time lost vDSO acceleration on older kernels

[adhemerval.zanella at linaro dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=28071

Adhemerval Zanella <adhemerval.zanella at linaro dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
   Target Milestone|---                         |2.34
         Resolution|---                         |FIXED
                 CC|                            |adhemerval.zanella at linaro dot o
                   |                            |rg

--- Comment #3 from Adhemerval Zanella <adhemerval.zanella at linaro dot org> ---
Fixed upstream (72e84d1db22203e01a43268de71ea8669eca2863).

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