On Sat, 22 Apr 2000, Matthew Dillon wrote:
>
> :extend (using truncate) and then mmap() the destination file, then
> :read() directly into the mmap()'d portion.
> :
> :I'd like to see what numbers you get. :)
> :
> :--
> :-Alfred Perlstein - [[EMAIL PROTECTED]|[EMAIL PROTECTED]]
>
> Probably not so good considering the number of faults that will
> be taken. Also, if the destination filesystem runs out of room
> cp will take a random seg-fault trying to access the map. Plus
> the dirtying of that many VM pages will seriously effect performance.
Err... I think what Alfred (should have) meant was that you should mmap
the source file and madvise it MADV_SEQUENTIAL, then write() to the new
file directly from that. How bad do you foresee performance being then?
--
Brian Fundakowski Feldman \ FreeBSD: The Power to Serve! /
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