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.\" -*- nroff -*-
.TH SRAW 8 "Nov 1993"
.SH NAME
sraw \- benchmark raw scsi I/O performance under linux
.SH SYNOPSIS
.B sraw
.B scsi-device
[
.B bstart
[
.B bstep
] ]
.SH DESCRIPTION
This program was written because of all of the whining on the SCSI
channel about poor performance of the scsi drivers. This program basically
reads the specified scsi device and measures the throughput. Note that
the filesystem *AND* the buffer cache are bypassed by this code, this
program was designed to benchmark the naked scsi drivers by themselves
without the need to account for the overhead of any other portion of the
kernel.
.P
This program does a series of reads of the disk, of consecutive
areas on the disk. The device is first queried to determine the
sector size for the device, and then the series of reads is begun.
About 5.0 Mb is read from the device, and then the performance numbers
are reported. Note that since the buffer cache is completely bypassed,
there is no need to be concerned about cache hits or anything.
.P
Output of
.B
sraw
is a set of lines, 4 numbers per line:
.I blocksize, elapsed time, nblocks
and
.I throughput
(in bytes per second).
.SH OPTIONS
.TP
.I bstart
starting block to check different zones on ZBR discs
.TP
.I bstep
factor for sequential stepping, default 1.
Use 0 for reading always the same blocks (from cache)
.SH AUTHOR
.B sraw
was written by Eric Youngdale.
.SH AVAILABILITY
.B sraw
is available at
.nf
.B ftp://tsx-11.mit.edu/pub/linux/ALPHA/scsi/
.fi
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