Re: Performance improvement with Akira Tsukamoto's Athlon copy_user patch

[Akira Tsukamoto <at541@columbia.edu>]

Hi Calin,

> 2.5.47 with copy user patch
> 
> /dev/hda:
>  Timing buffer-cache reads:   128 MB in  0.71 seconds =180.28 MB/sec
>  Timing buffered disk reads:  64 MB in  4.06 seconds = 15.78 MB/sec
> 
> 
> vanila 2.5.47
> 
> /dev/hda:
>  Timing buffer-cache reads:   128 MB in  1.09 seconds =117.32 MB/sec
>  Timing buffered disk reads:  64 MB in  4.05 seconds = 15.78 MB/sec

Thank you for trying, 
I also been using for compiling kernel for several days,
but, as Andi mentioned, currently the aki_copy is *dangerous* 
when any processes/threads ara using fpu register.

I read the code of laze FPU state saving and confirmed that 
if the function does not generate exception than
'kernel_fpu_begin/end()' should assure fpu safe inside kernel.

However, it is not enough where exception could rise, as Takahashi
mentioned.

I also have benchmark for small buffer which is enough to fit in cache
which I would like to show that aki_copy does perform well for this 
circumstances. 
But I have something urgent todo(homework :)) and I will come back to it
as soon as possible.

Thank you,

Akira Tsukamoto

On Tue, 19 Nov 2002 18:34:16 +0100 (CET)
szonyi calin <caszonyi@yahoo.com> mentioned:

> Hello everybody 
> 
> I patched yesterday the 2.5.47 vanilla kernel with Akira
>  Tsukamoto's Athlon copy_user patch and tried a 
> hdparm -tT /dev/hda 
> 
> The results (atached) are impressive compared with both the 
> vanilla 2.5.47 kernel and the 2.4.19 with ck-rl5 patches (from
>  colivas)
> 
> Bye
> 
> Calin
> 
> 
> 
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-- 
Akira Tsukamoto <akira-t@suna-asobi.com, at541@columbia.edu>