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+perf-iostat(1)
+===============
+
+NAME
+----
+perf-iostat - Show I/O performance metrics
+
+SYNOPSIS
+--------
+[verse]
+'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
+--------
+linkperf:perf-stat[1]