iothreadset

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Configure runtime parameters of I/O threads for a virtual server.

Syntax

Where:

<IOthread-ID>: Is the ID of the I/O thread to be configured of virtual server. The I/O thread ID must be beyond the range of available I/O threads.
<VS>: Is the name, ID, or UUID of the virtual server.

Selected options

--config: Affects the virtual server the next time it is restarted.
--cpulist <cpus>: Specifies which host CPUs the I/O thread is allowed to run on.
--current: Affects the current virtual server.
--live: Affects the current virtual server only if it is running.
--poll-grow <grow_value>: Controls how quickly the polling interval increases when polling is effective. A higher value results in faster duration increases.
--poll-max-ns <maximum_time>: Specifies the maximum time (in nanoseconds) that the I/O thread is allowed to poll before it stops and blocks.
--poll-shrink <shrink_value>: Controls how quickly the polling interval decreases when polling is not effective. A higher value results in faster duration reductions.
--poll-weight <weight_value>: Specifies the weight (valid range=0-63, where weight="0" uses the default value of 3) of how recent I/O activity influences polling intervals to balance CPU efficiency and I/O performance. Lower values increase the weight of recent I/O activity which results in faster adaptations. The default value is 3.

Usage

Configuring I/O thread polling parameters

Example

This example shows the iothreadinfoset command:

# virsh iothreadset vserv1 1 --poll-max-ns 50000 --poll-grow 2 --poll-shrink 2 --poll-weight 2 --live
 
      
# virsh domstats vserv1 --iothread
Domain: vserv1
   iothread.count=1
   iothread.1.poll-max-ns=50000 
   iothread.1.poll-grow=2
   iothread.1.poll-shrink=2
   iothread.1.poll-weight=2