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DateMon, 9 Apr 2007 11:50:21 -0700 (PDT)
FromChristoph Lameter <>
SubjectRe: [QUICKLIST 1/4] Quicklists for page table pages V5
On Mon, 9 Apr 2007, Andrew Morton wrote:

> On Mon,  9 Apr 2007 11:25:09 -0700 (PDT)
> Christoph Lameter <clameter@sgi.com> wrote:
> 
> > On x86_64 this cuts allocation overhead for page table pages down to
> > a fraction (kernel compile / editing load. TSC based measurement
> > of times spend in each function):
> > 
> > no quicklist
> > 
> > pte_alloc               1569048 4.3s(401ns/2.7us/179.7us)
> > pmd_alloc                780988 2.1s(337ns/2.7us/86.1us)
> > pud_alloc                780072 2.2s(424ns/2.8us/300.6us)
> > pgd_alloc                260022 1s(920ns/4us/263.1us)
> > 
> > quicklist:
> > 
> > pte_alloc                452436 573.4ms(8ns/1.3us/121.1us)
> > pmd_alloc                196204 174.5ms(7ns/889ns/46.1us)
> > pud_alloc                195688 172.4ms(7ns/881ns/151.3us)
> > pgd_alloc                 65228 9.8ms(8ns/150ns/6.1us)
> > 
> > pgd allocations are the most complex and there we see the most dramatic
> > improvement (may be we can cut down the amount of pgds cached somewhat?).
> > But even the pte allocations still see a doubling of performance.
> 
> Was there any observeable change in overall runtime?

The kernel compile times fluctuates as usual. There was a tendency for the 
times to be less but no clear win as discussed before.

> What are the numbers in parentheses?

(minimum/average/maximum) 
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