diff options
| author | ps <ps@FreeBSD.org> | 2000-10-17 10:05:49 +0000 |
|---|---|---|
| committer | ps <ps@FreeBSD.org> | 2000-10-17 10:05:49 +0000 |
| commit | c71ac689e04ce39d113325e3854477539dae464c (patch) | |
| tree | 331cd4cbe2e1e3d9d7734fa4fce3e6a5554d434c /sys/i386/include/param.h | |
| parent | 26207dd1489dfcba9ad2215401292904446e000a (diff) | |
| download | FreeBSD-src-c71ac689e04ce39d113325e3854477539dae464c.zip FreeBSD-src-c71ac689e04ce39d113325e3854477539dae464c.tar.gz | |
Implement write combining for crashdumps. This is useful when
write caching is disabled on both SCSI and IDE disks where large
memory dumps could take up to an hour to complete.
Taking an i386 scsi based system with 512MB of ram and timing (in
seconds) how long it took to complete a dump, the following results
were obtained:
Before: After:
WCE TIME WCE TIME
------------------ ------------------
1 141.820972 1 15.600111
0 797.265072 0 65.480465
Obtained from: Yahoo!
Reviewed by: peter
Diffstat (limited to 'sys/i386/include/param.h')
| -rw-r--r-- | sys/i386/include/param.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/sys/i386/include/param.h b/sys/i386/include/param.h index bac527e..0d17297 100644 --- a/sys/i386/include/param.h +++ b/sys/i386/include/param.h @@ -96,6 +96,7 @@ #endif #define DFLTPHYS (64 * 1024) /* default max raw I/O transfer size */ #define MAXPHYS (128 * 1024) /* max raw I/O transfer size */ +#define MAXDUMPPGS (DFLTPHYS/PAGE_SIZE) #define IOPAGES 2 /* pages of i/o permission bitmap */ #define UPAGES 2 /* pages of u-area */ |
