Messages in this thread | | | From | Roger Leigh <> | Subject | Re: 2.6.16-rc2 powerpc timestamp skew | Date | Mon, 13 Feb 2006 18:34:34 +0000 |
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Benjamin Herrenschmidt <benh@kernel.crashing.org> writes:
> On Sun, 2006-02-12 at 17:13 +0000, Roger Leigh wrote: >> Hi folks, >> >> When running a 2.6.16-rc2 kernel on a powerpc system (Mac Mini; >> Freescale 7447A): >> >> $ date && touch f && ls -l f && rm -f f && date >> Sun Feb 12 12:20:14 GMT 2006 >> -rw-r--r-- 1 rleigh rleigh 0 2006-02-12 12:23 >> Sun Feb 12 12:20:14 GMT 2006 >> >> Notice the timestamp is 3 minutes in the future compared with the >> system time. "make" is not a very happy bunny running on this kernel >> due to every touched file being 3 minutes in the future. >> >> When the same command is run on 2.6.15.3: >> >> $ date && touch f && ls -l f && rm -f f && date >> Sun Feb 12 14:27:27 GMT 2006 >> -rw-r--r-- 1 rleigh rleigh 0 2006-02-12 14:27 >> Sun Feb 12 14:27:27 GMT 2006 >> >> In this case the times are identical, as you would expect. >> >> In both these cases, the chrony NTP daemon is running, if that might >> be a problem. > > Can you strace vs. ltrace and see if the gettimeofday or clock_gettime > syscalls are ever called ?
| strace | ltrace -----------+---------------+------------------------------------ 2.6.15 | | date | clock_gettime | clock_gettime -> SYS_clock_gettime, | | localtime, strftime touch | utimes | futimes -> SYS_utimes | | 2.6.16-rc2 | | date | clock_gettime | clock_gettime -> SYS_clock_gettime, | | localtime, strftime touch | utimes | futimes -> SYS_utimes
[clock_gettime(CLOCK_REALTIME, {1139826613, 157402000}) = 0]
> I wonder if you have a glibc new enough to > use the vDSO to obtain the time or if it's using the syscall... The vDSO > on ppc32 is very new.
It's glibc 2.3.5 (Debian libc6 2.3.5-13).
> Also, are your kernels built with ARCH=ppc or ARCH=powerpc ?
ppc.
Thanks, Roger
-- Roger Leigh Printing on GNU/Linux? http://gutenprint.sourceforge.net/ Debian GNU/Linux http://www.debian.org/ GPG Public Key: 0x25BFB848. Please sign and encrypt your mail. [unhandled content-type:application/pgp-signature] | |