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Date: Fri, 29 Dec 2006 10:38:24 -0700
From: Eric Blake <ebb9 AT byu DOT net>
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To: cygwin AT cygwin DOT com
Subject: Re: cp vs native copy performance; suboptimal st_blksize?
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According to Brian Ford on 12/28/2006 2:15 PM:
>
> Current cp gets its initial buffer size from the st_blksize field
> returned by fstat, which is currently set to 1k.  I have found several
> references on the web that state 64k is the "native" I/O size for the
> disk cache manager.  This might also fix the infamous USB transfer
> rate issue as discussed here:
>
> http://www.cygwin.com/ml/cygwin/2006-08/msg00090.html
>
> Should we change st_blksize to 64k for performance reasons?
> The benefit is non-trivial, IMHO.

There is also the question of whether using posix_fallocate and
posix_fadvise will help matters; it is something I've been meaning to get
to, but as it currently depends on 1.7.x snapshots, it hasn't been my
highest priority.

- --
Don't work too hard, make some time for fun as well!

Eric Blake             ebb9 AT byu DOT net
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