On 29/08/17 15:55, Konrad Rzeszutek Wilk wrote: > On Tue, Aug 29, 2017 at 11:46:35AM +0000, Yang Zhang wrote: >> So far, pv_idle_ops.poll is the only ops for pv_idle. .poll is called in >> idle path which will polling for a while before we enter the real idle >> state. >> >> In virtualization, idle path includes several heavy operations >> includes timer access(LAPIC timer or TSC deadline timer) which will hurt >> performance especially for latency intensive workload like message >> passing task. The cost is mainly come from the vmexit which is a >> hardware context switch between VM and hypervisor. Our solution is to >> poll for a while and do not enter real idle path if we can get the >> schedule event during polling. >> >> Poll may cause the CPU waste so we adopt a smart polling mechanism to >> reduce the useless poll. >> >> Signed-off-by: Yang Zhang <yang.zhang.wz@xxxxxxxxx> >> Signed-off-by: Quan Xu <quan.xu0@xxxxxxxxx> >> Cc: Jeremy Fitzhardinge <jeremy@xxxxxxxx> >> Cc: Chris Wright <chrisw@xxxxxxxxxxxx> >> Cc: Alok Kataria <akataria@xxxxxxxxxx> >> Cc: Rusty Russell <rusty@xxxxxxxxxxxxxxx> >> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> >> Cc: Ingo Molnar <mingo@xxxxxxxxxx> >> Cc: "H. Peter Anvin" <hpa@xxxxxxxxx> >> Cc: x86@xxxxxxxxxx >> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> >> Cc: Andy Lutomirski <luto@xxxxxxxxxx> >> Cc: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx> >> Cc: Pan Xinhui <xinhui.pan@xxxxxxxxxxxxxxxxxx> >> Cc: Kees Cook <keescook@xxxxxxxxxxxx> >> Cc: virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx >> Cc: linux-kernel@xxxxxxxxxxxxxxx > > Adding xen-devel. > > Juergen, we really should replace Jeremy's name with xen-devel or > your name.. I wouldn't mind being added. What does Jeremy think of being removed? > Wasn't there an patch by you that took some of the > mainternship over it? I added include/linux/hypervisor.h to the PARAVIRT section and offered to maintain it in case the PARAVIRT maintainers didn't want to. Juergen
