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| author | Bruce Evans <bde@FreeBSD.org> | 1998-08-18 03:54:39 +0000 |
|---|---|---|
| committer | Bruce Evans <bde@FreeBSD.org> | 1998-08-18 03:54:39 +0000 |
| commit | 1874ef935c44cb787323b4c9c0bf7c81cac0c34f (patch) | |
| tree | b57195bb1f4597d9a801a63f40a203a452e53bd4 /sys/gnu | |
| parent | 4b82d708ae97800b9b0534c220d0c08907810e2f (diff) | |
| download | src-1874ef935c44cb787323b4c9c0bf7c81cac0c34f.tar.gz src-1874ef935c44cb787323b4c9c0bf7c81cac0c34f.zip | |
Quick fix for breakage of read clustering on non-IDE drives. Read
clustering is obsolescent technology so hardly anyone noticed. On
a DORS 32160 SCSI drive with 4 tags, read clustering makes very
little difference even for huge sequential reads. However, on a
ZIP SCSI drive with 0 tags, the minimum overhead per block is about
40 msec, so very large clusters must be used to get anywhere near
the maximum transfer rate. Using clusters consisting of 1 8K block
reduces the transfer rate to about 250K/sec. Under msdosfs, missing
read clustering is normal and a cluster size of 1 512 byte block
reduces the transfer rate to about 25K/sec.
Broken in: rev.1.18
Notes
Notes:
svn path=/head/; revision=38418
Diffstat (limited to 'sys/gnu')
| -rw-r--r-- | sys/gnu/ext2fs/ext2_bmap.c | 4 | ||||
| -rw-r--r-- | sys/gnu/fs/ext2fs/ext2_bmap.c | 4 |
2 files changed, 4 insertions, 4 deletions
diff --git a/sys/gnu/ext2fs/ext2_bmap.c b/sys/gnu/ext2fs/ext2_bmap.c index 176b7dc1e1c5..86638856d872 100644 --- a/sys/gnu/ext2fs/ext2_bmap.c +++ b/sys/gnu/ext2fs/ext2_bmap.c @@ -36,7 +36,7 @@ * SUCH DAMAGE. * * @(#)ufs_bmap.c 8.7 (Berkeley) 3/21/95 - * $Id: ufs_bmap.c,v 1.20 1998/02/06 12:14:17 eivind Exp $ + * $Id: ufs_bmap.c,v 1.21 1998/07/04 20:45:39 julian Exp $ */ #include <sys/param.h> @@ -163,7 +163,7 @@ ufs_bmaparray(vp, bn, bnp, ap, nump, runp, runb) maxrun -= 1; } - if (maxrun == 0) { + if (maxrun <= 0) { vp->v_maxio = DFLTPHYS; maxrun = DFLTPHYS / blksize; maxrun -= 1; diff --git a/sys/gnu/fs/ext2fs/ext2_bmap.c b/sys/gnu/fs/ext2fs/ext2_bmap.c index 176b7dc1e1c5..86638856d872 100644 --- a/sys/gnu/fs/ext2fs/ext2_bmap.c +++ b/sys/gnu/fs/ext2fs/ext2_bmap.c @@ -36,7 +36,7 @@ * SUCH DAMAGE. * * @(#)ufs_bmap.c 8.7 (Berkeley) 3/21/95 - * $Id: ufs_bmap.c,v 1.20 1998/02/06 12:14:17 eivind Exp $ + * $Id: ufs_bmap.c,v 1.21 1998/07/04 20:45:39 julian Exp $ */ #include <sys/param.h> @@ -163,7 +163,7 @@ ufs_bmaparray(vp, bn, bnp, ap, nump, runp, runb) maxrun -= 1; } - if (maxrun == 0) { + if (maxrun <= 0) { vp->v_maxio = DFLTPHYS; maxrun = DFLTPHYS / blksize; maxrun -= 1; |