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On Friday 10 December 2004 05:53, Ingo Molnar wrote: >* Ingo Molnar <mingo@elte.hu> wrote: >> this smells too. [...] Humm, something else does too Ingo. Amanda failed on this machine last night, and so did an amcheck just now, returning this: [amanda@coyote driver]$ amcheck Daily Amanda Tape Server Host Check ----------------------------- Holding disk /dumps: 26444 MB disk space available, using 25944 MB amcheck-server: slot 8: date 20041210 label Dailys-8 (active tape) amcheck-server: slot 9: date 20041124 label Dailys-9 (exact label match) NOTE: skipping tape-writable test Tape Dailys-9 label ok Server check took 0.386 seconds Amanda Backup Client Hosts Check -------------------------------- WARNING: coyote: selfcheck reply timed out. Client check: 2 hosts checked in 22.199 seconds, 1 problem found (brought to you by Amanda 2.4.5b1-20041122) ------------------ This was while running 32-12, which otherwise feels good and gave me no other indication of a problem. I've also looked at the log, but its silent on this subject. I'll get the latest and try it. >found two brown-paperbag bugs that caused bad latencies in the -RT >kernel: when i added PREEMPT_DIRECT (which first showed up in > -32-10) i also added a missed-reschedule bug to try_to_wake_up() > and to mutex/semaphore-unlock (__up()). Oops. > >i dont think this bug could explain a msec-range latency because the >syscall return path should catch the missed reschedule and it would > need continuous syscall execution in the milliseconds range by a > lowprio task for a latency to be transported to latencytest, but > certainly the bug doesnt help latencies. The -32-15 kernel can be > downloaded from the usual place: > > http://redhat.com/~mingo/realtime-preempt/ > >other changes in -32-15: more work on the tracer, cleaner trace > output and the tracing of syscall entries and returns, with > arguments and return values displayed as well (i.e. a simple strace > variant). Here is how a syscall now looks like in > /proc/latency_trace: > > loop-tes-3885 0.... 100µs > sys_getppid (002fcffc 00000001 > 0000007b) loop-tes-3885 0.... 101µs+: sys_getppid > (sysenter_past_esp) loop-tes-3885 0d... 103µs < (3868) > >'< (return-val)' is the syscall return value, '> sys_name(params)' > is the syscall itself. (note that the return path is also used by > interrupts, so it's not purely a syscall-return point) This makes > it easier to track userspace execution. > > Ingo >- >To unsubscribe from this list: send the line "unsubscribe > linux-kernel" in the body of a message to majordomo@vger.kernel.org >More majordomo info at http://vger.kernel.org/majordomo-info.html >Please read the FAQ at http://www.tux.org/lkml/ -- Cheers, Gene "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) 99.30% setiathome rank, not too shabby for a WV hillbilly Yahoo.com attorneys please note, additions to this message by Gene Heskett are: Copyright 2004 by Maurice Eugene Heskett, all rights reserved. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ | ||||||||||||
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