On 20/06/13 11:38, Jan Beulich wrote: >>>> On 19.06.13 at 17:25, David Vrabel <david.vra...@citrix.com> wrote: >> syscore_suspend() and syscore_resume() expect there to be only one >> online CPU. e.g., hrtimers_resume() only triggers events for the >> current CPU. Xen's suspend path was leaving all VCPUs online and then >> attempting to fixup problems afterwards (e.g., with an explicit call >> to clock_was_set() to trigger pending high resolution timers). >> >> Instead, disable non-boot CPUs before calling stop_machine() and >> reenable them afterwards. > > In XenoLinux the so called "fast suspend" mode was specifically > added for performance reasons, and it looks like to date pv-ops > only ever supported that mode. So one question is whether > there's going to be any bad performance effect from this.
Yes :( On a VM with 4 VCPUs, disable_boot_cpus() took > 200 ms. I'll have to rethink this. David -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
