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

[Blue Swirl]

On Sun, Dec 5, 2010 at 7:14 AM, Kirill Batuzov <address@hidden> wrote:
> 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.

OK. Thanks, applied.