This is the mail archive of the
libc-alpha@sourceware.org
mailing list for the glibc project.
Re: Loss of vDSO support on s390x
* Stefan Liebler:
> According to <kernel>/arch/s390/kernel/vdso64/clock_gettime.S there is
> support for:
> - CLOCK_MONOTONIC
> - CLOCK_MONOTONIC_COARSE
> - CLOCK_REALTIME_COARSE
> - CLOCK_REALTIME
> - CPUCLOCK_VIRT for this thread
> (See
> https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/tree/arch/s390/kernel/vdso64/clock_gettime.S?id=2115fbf7210bd053ba55a95e7ebc366df41aa9cf)
Hmm. Looks like I'm missing this kernel commit:
commit b7eacb59cd7fb5e98852186e485c0c865f862645
Author: Martin Schwidefsky <schwidefsky@de.ibm.com>
Date: Fri Aug 29 12:31:45 2014 +0200
s390/vdso: add vdso support for coarse clocks
Add CLOCK_REALTIME_COARSE and CLOCK_MONOTONIC_COARSE optimization to
the 64-bit and 31-bit vdso.
That went into 3.18, so maybe that's old enough. It will impact people
who run newer containers on el7 hosts, though. Maybe we should request
a backport of that commit?
> Do you run on s390x (64bit) or s390 (31bit)?
It's s390x. I expect s390 to be worse (as you showed), but I'm not sure
if we need to fix it proactively.
Thanks,
Florian