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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