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[Qemu-devel] Re: [kvm-devel] [PATCH/RFC 4/4] Add support for dynamic tic
From: |
Matthew Kent |
Subject: |
[Qemu-devel] Re: [kvm-devel] [PATCH/RFC 4/4] Add support for dynamic ticks. |
Date: |
Fri, 17 Aug 2007 00:16:09 -0700 (PDT) |
User-agent: |
SquirrelMail/1.4.9a |
> If DYNAMIC_TICKS is defined qemu does not attepmt to generate SIGALRM at a
> constant rate. Rather, the system timer is set to generate SIGALRM only
> when it is needed. DYNAMIC_TICKS reduces the number of SIGALRMs sent to
> idle dynamic-ticked guests.
> Original patch from Dan Kenigsberg <address@hidden>
>
> Signed-off-by: Luca Tettamanti <address@hidden>
Wow, this patch sure made a difference for some timings I've been doing
with kvm-35 and hackbench. All tests using 2.6.23-rc3+hrtimers patch for
x86_64/i386 tickless and a quad core intel:
address@hidden ~]$ time ./hackbench 50
x86_64 host : real 0m10.845s
x86_64 host, bound to 1 cpu : real 0m21.884s
i386 guest+unix clock : real 0m49.206s
i386 guest+hpet clock : real 0m48.292s
i386 guest+dynticks clock : real 0m28.835s
Results are repeatable and verfied with a stopwatch because I didn't
believe them at first :)
Great stuff.
--
Matthew Kent <address@hidden>
http://magoazul.com
[Qemu-devel] Re: [kvm-devel] [PATCH/RFC 0/4] Rework alarm timer infrastrucure., Avi Kivity, 2007/08/17