PERF-IOSTAT(1)

NAME
perf-iostat - Show I/O performance metrics

SYNOPSIS

perf iostat list
perf iostat <ports> -- <command> [<options>]

DESCRIPTION

Mode is intended to provide four I/O performance metrics per each PCIe root port:

    • Inbound Read - I/O devices below root port read from the host memory, in MB

    • Inbound Write - I/O devices below root port write to the host memory, in MB

    • Outbound Read - CPU reads from I/O devices below root port, in MB

    • Outbound Write - CPU writes to I/O devices below root port, in MB

OPTIONS

<command>...
    Any command you can specify in a shell.

list
    List all PCIe root ports.

<ports>
    Select the root ports for monitoring. Comma-separated list is supported.

EXAMPLES

    1. List all PCIe root ports (example for 2-S platform):

        $ perf iostat list
        S0-uncore_iio_0<0000:00>
        S1-uncore_iio_0<0000:80>
        S0-uncore_iio_1<0000:17>
        S1-uncore_iio_1<0000:85>
        S0-uncore_iio_2<0000:3a>
        S1-uncore_iio_2<0000:ae>
        S0-uncore_iio_3<0000:5d>
        S1-uncore_iio_3<0000:d7>

    2. Collect metrics for all PCIe root ports:

        $ perf iostat -- dd if=/dev/zero of=/dev/nvme0n1 bs=1M oflag=direct
        357708+0 records in
        357707+0 records out
        375083606016 bytes (375 GB, 349 GiB) copied, 215.974 s, 1.7 GB/s

        Performance counter stats for 'system wide':

           port             Inbound Read(MB)    Inbound Write(MB)    Outbound Read(MB)   Outbound Write(MB)
        0000:00                    1                    0                    2                    3
        0000:80                    0                    0                    0                    0
        0000:17               352552                   43                    0                   21
        0000:85                    0                    0                    0                    0
        0000:3a                    3                    0                    0                    0
        0000:ae                    0                    0                    0                    0
        0000:5d                    0                    0                    0                    0
        0000:d7                    0                    0                    0                    0

    3. Collect metrics for comma-separated list of PCIe root ports:

        $ perf iostat 0000:17,0:3a -- dd if=/dev/zero of=/dev/nvme0n1 bs=1M oflag=direct
        357708+0 records in
        357707+0 records out
        375083606016 bytes (375 GB, 349 GiB) copied, 197.08 s, 1.9 GB/s

        Performance counter stats for 'system wide':

           port             Inbound Read(MB)    Inbound Write(MB)    Outbound Read(MB)   Outbound Write(MB)
        0000:17               358559                   44                    0                   22
        0000:3a                    3                    2                    0                    0

        197.081983474 seconds time elapsed

SEE ALSO

perf-stat(1)