Messages in this thread | | | Date | Mon, 13 Dec 2004 07:50:09 -0700 (MST) | From | Zwane Mwaikambo <> | Subject | Re: dynamic-hz |
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On Mon, 13 Dec 2004, Andrea Arcangeli wrote:
> You were the one making the case of the NMI, the NMI will screw > completely any attempt of rearming the TSC accurately (though I don't > mind too much, like for the sti; hlt, since NMI is pratically impossible > to trigger in production, if a NMI is fired we've more troubles than the > 1/HZ latency on a pending wakeup or on the system time taking the > tangent ;)
I wouldn't say that NMI isn't used in production, if we didn't cater for NMI it'd be hard to do high sample rate profiling with Oprofile and dynamic-hz. I consider (non)kernel developers profiling code on systems as production use.
> (btw, my firewall systemtime will get fixed too by dyanmic-hz HZ=100, > it's pure waste to keep my firewall at HZ=1000 even if I didn't have > constant irq-latency of 3/4msec [measured with rdtsc], though I didn't > mention this yet because dynamic-hz in my firewall case would be a pure > band-aid, even fixing the tick-lost adjustment would be a band-aid, the > only thing to fix is the usb irq that runs for 3/4msec without returning).
I have a few personal systems which really would benefit too ;)
Thanks, Zwane
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