Messages in this thread | | | Date | Tue, 15 Jan 2008 12:46:29 +0000 | From | Paulo Marques <> | Subject | Re: [RFC] mmaped copy too slow? |
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KOSAKI Motohiro wrote: > Hi > > at one point, I found the large file copy speed was different depending on > the copy method. > > I compared below method > - read(2) and write(2). > - mmap(2) x2 and memcpy. > - mmap(2) and write(2). > > in addition, effect of fadvice(2) and madvice(2) is checked. > > to a strange thing, > - most faster method is read + write + fadvice. > - worst method is mmap + memcpy.
One thing you could also try is to pass MAP_POPULATE to mmap so that the page tables are filled in at the time of the mmap, avoiding a lot of page faults later.
Just my 2 cents,
-- Paulo Marques - www.grupopie.com
"All I ask is a chance to prove that money can't make me happy."
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