IOTOP(8) | System Manager's Manual | IOTOP(8) |
iotop - simple top-like I/O monitor
iotop [OPTIONS]
iotop watches I/O usage information output by the Linux kernel (requires 2.6.20 or later) and displays a table of current I/O usage by processes or threads on the system. At least the CONFIG_TASK_DELAY_ACCT, CONFIG_TASK_IO_ACCOUNTING, CONFIG_TASKSTATS and CONFIG_VM_EVENT_COUNTERS options need to be enabled in your Linux kernel build configuration and since Linux kernel 5.14, the kernel.task_delayacct sysctl enabled.
iotop displays columns for the I/O bandwidth read and written by each process/thread during the sampling period. It also displays the percentage of time the thread/process spent while swapping in and while waiting on I/O. For each process, its I/O priority (class/level) is shown.
In addition, the total I/O bandwidth read and written during the sampling period is displayed at the top of the interface. Total DISK READ and Total DISK WRITE values represent total read and write bandwidth between processes and kernel threads on the one side and kernel block device subsystem on the other. While Current DISK READ and Current DISK WRITE values represent corresponding bandwidths for current disk I/O between kernel block device subsystem and underlying hardware (HDD, SSD, etc.). Thus Total and Current values may not be equal at any given moment of time due to data caching and I/O operations reordering that take place inside Linux kernel.
Use the left and right arrows to change the sorting, r to reverse the sorting order, o to toggle the --only option, p to toggle the --processes option, a to toggle the --accumulated option, q to quit or i to change the priority of a thread or a process's thread(s). Any other key will force a refresh.
iotop was written by Guillaume Chazarain.
This manual page was started by Paul Wise for the Debian project and is placed in the public domain.
October 1, 2021 |