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Re: better buffer size for copy
From: |
Robert Latham |
Subject: |
Re: better buffer size for copy |
Date: |
Fri, 18 Nov 2005 16:27:54 -0600 |
User-agent: |
Mutt/1.5.9i |
(README says to ping if there's not been an ack of a patch after two
weeks. here i go)
This patch to today's (18 Nov 2005) coreutils CVS makes copy.c
consider both the source and destination blocksize when computing
buf_size. With this patch, src/copy.c will use the LCM of the soruce
and destination block sizes. As Paul suggested, I used the buffer_lcm
routine from diffutils.
For what it's worth, this patch does not introduce any regressions
into the coreutils testsuite.
When copying from a remote filesystem with a block size of 4MB to a
filesystem with a 4k blocksize, the copy is *very* slow. Going from a
filesystem with 4k blocks to a filesystem with 4MB blocks is much
faster. With this patch, both operations are equally performant.
I went ahead and added a ChangeLog entry as well.
Thanks. I'll be more than happy to incorporate any suggestions or
comments.
==rob
--
Rob Latham
Mathematics and Computer Science Division A215 0178 EA2D B059 8CDF
Argonne National Labs, IL USA B29D F333 664A 4280 315B
coreutils-lcm.patch
Description: Text document
- better buffer size for copy, Robert Latham, 2005/11/04
- Re: better buffer size for copy, Paul Eggert, 2005/11/05
- Re: better buffer size for copy, Robert Latham, 2005/11/07
- Re: better buffer size for copy, Paul Eggert, 2005/11/07
- Re: better buffer size for copy, Robert Latham, 2005/11/07
- Re: better buffer size for copy,
Robert Latham <=
- Re: better buffer size for copy, Phillip Susi, 2005/11/19
- Re: better buffer size for copy, Robert Latham, 2005/11/20
- Re: better buffer size for copy, Phillip Susi, 2005/11/21
- Re: better buffer size for copy, Robert Latham, 2005/11/22
- Re: better buffer size for copy, Phillip Susi, 2005/11/22
- Re: better buffer size for copy, Paul Eggert, 2005/11/24
- Re: better buffer size for copy, Jim Meyering, 2005/11/24