RE: [PATCH RFC] [x86] Optimize copy-page by reducing impact from HWprefetch

[Ma, Ling]

Hi Ingo
 
> Ling, mind double checking which one is the faster/better one on SNB,
> in cold-cache and hot-cache situations, copy_page or copy_page_c?
Copy_page_c 
on hot-cache copy_page_c on SNB combines data to 128bit (processor limit 128bit/cycle for write) after startup latency
so it is faster than copy_page which provides 64bit/cycle for write.

on cold-cache copy_page_c doesn't use prefetch, which uses prfetch according to copy size,
so copy_page function is better. 

Thanks
Ling

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/