| Date | Tue, 12 May 2015 11:33:49 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH 4/6] nohz: support PR_DATAPLANE_QUIESCE |
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On Fri, May 08, 2015 at 01:58:45PM -0400, Chris Metcalf wrote: > This prctl() flag for PR_SET_DATAPLANE sets a mode that requires the > kernel to quiesce any pending timer interrupts prior to returning > to userspace. When running with this mode set, sys calls (and page > faults, etc.) can be inordinately slow. However, user applications > that want to guarantee that no unexpected interrupts will occur > (even if they call into the kernel) can set this flag to guarantee > that semantics.
Currently people hot-unplug and hot-plug the CPU to do this. Obviously that's a wee bit horrible :-)
Not sure if a prctl like this is any better though. This is a CPU properly not a process one.
ISTR people talking about 'quiesce' sysfs file, along side the hotplug stuff, I can't quite remember.
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