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    SubjectRe: [PATCH 4/6] nohz: support PR_DATAPLANE_QUIESCE
    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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