Re: [PATCH] cat, cp, mv, install, split: Set the minimum IO block size used, to 64KiB

[Pádraig Brady]

On 04/30/2012 07:16 AM, Jim Meyering wrote:
> I think it's time to apply your patch:
> 
>     http://lists.gnu.org/archive/html/coreutils/2011-07/msg00059.html
> 
> Here are numbers from a 3.2GHz i7-970 with 1333MHz DDR3:
> 
>    1024=2.6 GB/s
>    2048=4.4 GB/s
>    4096=6.5 GB/s
>    8192=8.5 GB/s
>   16384=10.1 GB/s
>   32768=11.1 GB/s
>   65536=12.0 GB/s
>  131072=12.3 GB/s
>  262144=12.5 GB/s
>  524288=12.5 GB/s
> 1048576=12.6 GB/s
> 
> One minor suggestion: change s/1/2/ in "-sINT 1" here.
> 
>   +     timeout --foreground -sINT 1 \
>   +       dd bs=$bs if=/dev/zero of=/dev/null 2>&1 |
>   +        sed -n 's/.* \([0-9.]* [GM]B\/s\)/\1/p'
> 
> In this comment:
> 
>    for i in $(seq 0 10); do
>      bs=$((1024*2**$i))
>      printf "%7s=" $bs
>      timeout --foreground -sINT 2 \
>        dd bs=$bs if=/dev/zero of=/dev/null 2>&1 |
>          sed -n 's/.* \([0-9.]* [GM]B\/s\)/\1/p'
>    done
> 
> That makes the numbers more reproducible.
> Otherwise, for large block sizes, I'm guessing that the
> interrupted transfer can make too large a difference.
> 

Ok it's safe enough I think.
Pushed.

thanks!
Pádraig.