Re: [patch] readv/writev rework

[Andrew Morton <akpm@digeo.com>]

Andrew Morton wrote:
> 
> ...
> walk this linked list, writing the lines out.  The input was
> `cat linux/kernel/*.c > inputfile' and the output was written
> 1000 times (300 megs).  Benched four different ways of writing the
> output:
> 
>                     2.5.34         2.5.34-mm2         2.5.34-mm2-taka
> 
> write                 54s             54s                   55s
> fwrite                12.8s          12.8s                 12.7s
> fwrite_unlocked       11.6s          11.6s                 11.5s
> writev                39s            33.4s                 15.8s
> 
> So Janet's patch made a 15% improvement with this test.  Yours
> dropped it 50% again.
> 

I've retested with your latest patch.

                   2.5.34-mm4-taka2
write                  55.543
fwrite                 12.625
fwrite_unlocked        11.389
writev                  9.219

So that's another 70% speedup on top of yesterday's 100%, and kernel
beats glibc ;)