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)