Messages in this thread | | | Date | Wed, 21 Feb 2001 01:36:45 +0100 (MET) | From | Mikael Pettersson <> | Subject | Re: [PATCH] 2.4.1-ac UP-APIC updates |
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On Tue, 20 Feb 2001 16:00:53 -0500 (EST), Ingo Molnar wrote:
>my major gripe right now is that we still have bug reports that say that >systems hang when using nmi_watchdog=1 and work if nmi_watchdog=0. >Changing the NMI watchdog to be 1 Hz will make these bugreports "Linux >hangs once a week" instead of a "Linux hangs after 1-2 hours", which is >clearly hiding things and making debugging harder.
All reports I've seen have been for SMP kernels on MP machines using the IO-APIC to drive the watchdog. Are you saying there are also cases where UP boxes fail with nmi_watchdog non-zero? (My 1Hz change only affected the local APIC-driven watchdog which MP boxes normally don't use.)
>(and driving kernel-profiling from the NMI interrupt is a short-term >patch, so there is just no point in going to 1 Hz right now just to go >back to 100 Hz a few days later.)
Another "constructive" use of the perfctrs. Ok, this I can see wants a higher rate.
How far in the future is this? I'm concerned that the conflicting uses of the perfctrs (watchdog, kernel profiling, my perfctr driver for user-space performance measurements) is going to require some low-level request/release API.
>the rest of the changes are excellent - it's only the 100 Hz NMI issue i >have a problem with.
Ok.
Alan beat me to it for -ac20, so I'm not including a new patch now with the 1Hz bit backed out. Ingo, I guess this means the kernel profiling patch will have to "fix" the 1Hz thing by itself.
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