Re: page table lock patch V15 [0/7]: overview

Andrew Morton
2005-01-12T18:43:26Z

Christoph Lameter <clameter@sgi.com> wrote:
>
> > Do we have measurements of the negative and/or positive impact on smaller
> > machines?
>
> Here is a measurement of 256M allocation on a 2 way SMP machine 2x
> PIII-500Mhz:
>
> Gb Rep Threads User System Wall flt/cpu/s fault/wsec
> 0 10 1 0.005s 0.016s 0.002s 54357.280 52261.895
> 0 10 2 0.008s 0.019s 0.002s 43112.368 42463.566
>
> With patch:
>
> Gb Rep Threads User System Wall flt/cpu/s fault/wsec
> 0 10 1 0.005s 0.016s 0.002s 54357.280 53439.357
> 0 10 2 0.008s 0.018s 0.002s 44650.831 44202.412
>
> So only a very minor improvements for old machines (this one from ~ 98).

OK. But have you written a test to demonstrate any performance
regressions? From, say, the use of atomic ops on ptes?