Re: [Qemu-devel] [PATCH] Speedup 'tb_find_slow' by using the same heuristic as during memory page lookup

[Kirill Batuzov]

On 04.12.2010 23:11, Blue Swirl wrote:
> On Thu, Dec 2, 2010 at 1:12 PM, Kirill Batuzov<address@hidden>  wrote:
> > Move the last found TB to the head of the list so it will be found more quickly 
> > next time it will be looked for.
> >
> > Signed-off-by: Kirill Batuzov<address@hidden>
> > Signed-off-by: Pavel Yushchenko<address@hidden>
> > ---
> >
> > This patch appeared during investigation of performance issues with
> > S5PC110 emulation for Samsung. It increses OS startup speed significantly.
>
> The patch looks reasonable, but I didn't see any visible difference in
> my tests. Could you report your numbers?

The exact numbers depend on complexity of guest system.
 - For basic Debian system (no X-server) on versatilepb we observed 25% 
decrease of boot time.
 - For to-be released Samsung LIMO platform on S5PC110 board we 
observed 2x (for older version) and 3x (for newer version) decrease of 
boot time.
 - Small CPU-intensive benchmarks are not affected because they are 
completely handled by 'tb_find_fast'.

We also noticed better response time for heavyweight GUI applications, 
but I do not know how to measure it accurately.

----
  Kirill.