Manual: perf-iostat

PERF-IOSTAT(1)						 perf Manual					      PERF-IOSTAT(1)

NAME
       perf-iostat - Show I/O performance metrics

SYNOPSIS
       perf iostat list
       perf iostat  --  []

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

       list
	   List all PCIe root 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)

perf							 07/31/2026					      PERF-IOSTAT(1)