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Move existing contextsw-avoidance code in rzdump() earlier, since rzready() 

also calls biowait().

Some drives seek to modepage on every modepage geometry-sense in rzready()
cache dev_t of last readied device in rzdump() to elide rzready() calls.
2x speedup of dumps on rz25 and 20x-30x speedup on some IBM OEM 4gig drives.
This commit is contained in:
jonathan 1998-02-21 20:20:55 +00:00
parent d38d12d85a
commit f7bd3a0119
1 changed files with 20 additions and 11 deletions
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31
sys/arch/pmax/dev/rz.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: rz.c,v 1.34 1998/02/19 23:04:41 thorpej Exp $ */
/* $NetBSD: rz.c,v 1.35 1998/02/21 20:20:55 jonathan Exp $ */
/*
* Copyright (c) 1992, 1993
@ -39,7 +39,7 @@
*/
#include <sys/cdefs.h> /* RCS ID & Copyright macro defns */
__KERNEL_RCSID(0, "$NetBSD: rz.c,v 1.34 1998/02/19 23:04:41 thorpej Exp $");
__KERNEL_RCSID(0, "$NetBSD: rz.c,v 1.35 1998/02/21 20:20:55 jonathan Exp $");
/*
* SCSI CCS (Command Command Set) disk driver.
@ -1636,6 +1636,7 @@ rzdump(dev, blkno, va, size)
size_t size;
{
static int rzdoingadump;/* mutex */
static dev_t rzreadydev = NODEV; /* hint: device already rzready()ed */
int sectorsize; /* size of a disk sector */
int nsects; /* number of sectors in partition */
int sectoff; /* sector offset of partition */
@ -1661,9 +1662,23 @@ rzdump(dev, blkno, va, size)
if ((sc->sc_flags & RZF_ALIVE) == 0)
return (ENXIO);
if (rzready(sc) == 0) {
/* Drive didn't reset. */
return (ENXIO);
/*
* XXX Prevent the tsleep() calls in biowait() in rzready()
* XXX or later here from performing a switch.
*/
cold = 1;
/*
* Ready drive. rzready() does geometry-sense. Cache dev_t of
* last rzready()ed device to avoid seeks to modepage.
*/
if (rzreadydev != dev) {
if (rzready(sc) == 0) {
/* Drive didn't reset. */
rzreadydev = NODEV;
return (ENXIO);
}
rzreadydev = dev;
}
/*
@ -1686,12 +1701,6 @@ rzdump(dev, blkno, va, size)
/* Offset block number to start of partition. */
blkno += sectoff;
/*
* XXX Prevent the tsleep() done in biowait() below
* XXX from performing a switch.
*/
cold = 1;
while (totwrt > 0) {
nwrt = totwrt; /* XXX */
#ifndef RZ_DUMP_NOT_TRUSTED