Messages in this thread | | | Date | Mon, 4 May 2009 19:55:49 +0200 | From | Ingo Molnar <> | Subject | Re: Specific support for Intel Atom architecture |
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* Arjan van de Ven <arjan@infradead.org> wrote:
> On Mon, 4 May 2009 15:14:57 +0200 > Ingo Molnar <mingo@elte.hu> wrote: > > > > > * Tobias Doerffel <tobias.doerffel@gmail.com> wrote: > > > > > Am Sonntag, 3. Mai 2009 08:48:54 schrieb H. Peter Anvin: > > > > Willy Tarreau wrote: > > > > >> $(call cc-option,-march=atom,-march=i686) > > > > > > > > > > if it's an in-order architecture, wouldn't it be better to tune > > > > > for i386 or i486 instead ? > > > > > > > > Possibly. It would be worth measuring. > > > > > > How would one do that (never benchmarked kernel stuff before)? > > > > A standard method is to run lmbench and compare the results - > > lmbench has a built-in 'report comparison between two runs' > > feature. > > well... you're normally REALLY hard pressed to measure compiler > differences this way..... > > normally compiler options get benchmarked using speccpu and the > like....
Well, if there's no measurable difference in lmbench at all then the options probably dont matter that much. If some workload is found where compiler options show a difference then that matters. Speccpu only matters if those compiler options also help the kernel, in a measurable way.
Ingo
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