Re: [QUICKLIST 1/4] Quicklists for page table pages V5

Andrew Morton
2007-04-09T18:48:27Z

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?

What are the numbers in parentheses?