Re: sort: Parallel merging

[Shaun Jackman]

On Wed, 2010-02-17 at 13:27 -0800, Chen Guo wrote:
> Hi Shaun,
>     Last year someone named Glen Lenker did something like that, and I
> think the patch was rejected because the maintainers didn't see enough
> speed up as the number of CPUs got higher.

Thanks. I'll definitely look into this.

>     As for buffer size, I highly doubt using 8 mb, even if we're magically
> guaranteed to get 100% of the cpu cache, would work better than a larger
> buffer.
> 
>     The main reason would be for larger files, you'd have to repeatedly write
> temporary files out to disk, then merge those temporary files. Whatever
> time you save talking to cache is more than lost to the extra time talking
> to disk.

What if the temporary files were stored in RAM (i.e. tmpfs) rather than
on magnetic disk?

Cheers,
Shaun