K 10
svn:author
V 3
bde
K 8
svn:date
V 27
2004-03-13T02:56:27.000000Z
K 7
svn:log
V 646
Align the offset in vn_rdwr_inchunks() so that at most the first and
the last chunk are misaligned relative to a MAXBSIZE byte boundary.
vn_rdwr_inchunks() is used mainly for elf core dumps, and elf sections
are usually perfectly misaligned relative to MAXBSIZE, and chunking
prevents the file system from doing much realigning.

This gives a surprisingly large speedup for core dumps -- from 50 to
13 seconds for a 512MB core dump here.  The pessimization was mostly
from an interaction of the misalignment with IO_DIRECT.  It increased
the number of i/o's for each chunk by a factor of 5 (3 writes and 2
read-before-writes instead of 1 write).

END