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diff --git a/system_cmds/iosim.tproj/iosim.1 b/system_cmds/iosim.tproj/iosim.1 new file mode 100644 index 0000000..a3e8719 --- /dev/null +++ b/system_cmds/iosim.tproj/iosim.1 @@ -0,0 +1,100 @@ +.\" Copyright (c) 2013, Apple Inc. All rights reserved. +.\" +.Dd Oct 9, 2013 +.Dt IOSIM 1 +.Sh NAME +.Nm iosim +.Nd A performance tool to simulate I/O workloads. +.Sh SYNOPSIS +.Pp +.Nm iosim +.Ar -c <number> +Burst Count. No. of I/Os performed in an I/O burst. +Default Value: 10 +Valid Range: [0, INT_MAX] +.Pp +.Nm iosim +.Ar -i <msecs> +Inter Burst Duration. Amount of time each thread sleeps between bursts (-1 indicates random durations between 0-100 msecs) +Default Value: 0 +Valid Range: [-1, INT_MAX] +.Pp +.Nm iosim +.Ar -d <msecs> +Inter I/O delay. Amount of time thread sleeps between issuing I/Os +Default Value: 0 +Valid Range: [0, INT_MAX] +.Pp +.Nm iosim +.Ar -t <number> +Thread count +Default Value: 1 +Valid Range: [0, 1000] +.Pp +.Nm iosim +.Ar -f <number> +Workload Type (0/1/2 : Read-Only/Write-Only/Mixed RW) +Default Value: 0 +Valid Range: [0, 2] +.Pp +.Nm iosim +.Ar -m <number> +I/O Pattern (0/1 : Sequential/Random) +Default Value: 0 +Valid Range: [0, 1] +.Pp +.Nm iosim +.Ar -j <bytes> +Size of I/O in bytes +Default Value: 4096 +Valid Range: [0, INT_MAX] +.Pp +.Nm iosim +.Ar -s <msecs> +Frequency of sync() calls +Default Value: 5000 +Valid Range: [0, INT_MAX] +.Pp +.Nm iosim +.Ar -l <number> +I/O Tier (0/1/2/3) +Default Value: 0 +Valid Range: [0, 3] +.Pp +.Nm iosim +.Ar -z <number> +Size of the file created specified in pages (Only used when the file is being created by the tool) +Default Value: 1 GB +Valid Range: [0, INT_MAX] +.Pp +.Nm iosim +.Ar -x <secs> +Test duration (0 indicates that the tool would wait for a Ctrl-C) +Default Value: 0 +Valid Range: [0, INT_MAX] +.Pp +.Nm iosim +.Ar -a number +I/O Caching behavior (0/1 : Non-cached/Cached) +Default Value: 0 +Valid Range: [0, 1] +.Pp +.Nm iosim +.Ar -n <filename> +Filename for I/Os (If this option is not specified, the tool would create files on its own) +Valid Range: Valid filename +.Sh DESCRIPTION +The +.Nm iosim +tool allows simulating workloads for I/O performance evaluation. The tool spawns 'n' threads which issue non-cached I/Os. If specified, it also creates a sync thread which issues system wide sync() calls to flush data and metadata to disk (emulates launchd behavior). The I/Os are issued at the specified I/O tier and the tool reports latency and throughput numbers. +.P +.nf +Following is an explanation of the results: +Avg. Latency : Avg. latency experienced by the I/Os. +Low Latency Histogram: Frequency distribution of I/O latency for low latency I/Os. +Latency Histogram: Frequency distribution of I/O latency. +Burst Avg. Latency Histogram: Frequency distribution of burst avg. latency. +Throughput timeline: Time windowed throughput distrbution. +.fi +.Sh SEE ALSO +.Xr fs_usage 1 |