NAME

       oslat - OS Latency Detector

SYNOPSIS

       oslat [ -shvz ] [ -b bucket-size ] [ -B bias ] [ -c cpu-list ] [ -C cpu-main-thread ] [ -f rt-prio ] [
             --json filename ] [ -m workload-mem ] [-t runtime ] [ -T trace-threshold ] [ -w workload ] [ -W
             bucket-width ]

DESCRIPTION

       oslat is an open source userspace polling mode stress program to detect OS level latency.  The program
       runs a busy loop with no or various workloads, collecting TSC information and measuring the time
       frequently during the process.

OPTIONS

       -b, --bucket-size=N
              Specify the number of the buckets (4-1024).

       -B, --bias
              Add a bias to all the buckets using the estimated mininum.

       -c, --cpu-list=CPULIST
              Specify CPUs to run on.  For example, '1,3,5,7-15'.

       -C, --cpu-main-thread=CORE
              Specify which CPU the main thread runs on.  Default is cpu0.

       -f, --rtprio=PRIORITY
              Using  specific  SCHED_FIFO priority (1-99).  Otherwise use the default priority, normally it will
              be SCHED_OTHER.

       --json=FILENAME
              Write final results into FILENAME, JSON formatted.

       -m, --workload-mem=SIZE
              Size of the memory to use for the workload (e.g., 4K, 1M).  Total memory usage will be this  value
              multiplies  2*N,  because  there  will  be src/dst buffers for each thread, and N is the number of
              processors for testing.

       -D, --duration=TIME
              Specify test duration, e.g., 60, 20m, 2H (m/M: minutes, h/H: hours, d/D: days).   By  default  the
              unit is s/second.

       -T, --trace-threshold=THRESHOLD
              Stop  the  test when threshold triggered (in USEC).  At the meantime, print a marker in ftrace and
              stop ftrace too.

       -w, --workload=WORKLOAD
              Specify a kind of workload, default is no workload.  Options: "no", "memmove".

       -s, --single-preheat
              Use a single thread when measuring latency at  preheat  stage  NOTE:  please  make  sure  the  CPU
              frequency  on  all  testing cores are locked before using this parmater.  If you don't know how to
              lock the freq then please don't use this parameter.

       -W, --bucket-width
              Interval between buckets in nanoseconds

              NOTE: Widths not a multiple of 1000 cause ns-precision output You are responsible for  considering
              the impact of measurement overhead at the nanosecond scale.

       -h, --help
              Show the help message.

       -v, --version
              Show the version of the program.

       -z, --zero-omit
              Don't display buckets in the output histogram if all zeros.

AUTHOR

       oslat was written by Peter Xu <peterx@redhat.com>.

                                                 August 17, 2020                                        OSLAT(8)