Messages in this thread | | | Date | Thu, 12 Nov 2009 13:16:19 +0100 | From | Pavel Machek <> | Subject | Re: [PATCH RFC] [X86] performance improvement for memcpy_64.S by fast string. |
| |
> Ling, if you are interested, could you send a user-space test-app to > this thread that everyone could just compile and run on various older > boxes, to gather a performance profile of hand-coded versus string ops > performance? > > ( And i think we can make a judgement based on cache-hot performance > alone - if then the strings ops will perform comparatively better in > cache-cold scenarios, so the cache-hot numbers would be a conservative > estimate. )
Ugh, really? I'd expect cache-cold performance to be not helped at all (memory bandwidth limit) and you'll get slow down from additional i-cache misses... Pavel
-- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
| |