qm: IO thread: mention that setting can also help with hangs

See https://bugzilla.kernel.org/show_bug.cgi?id=199727

Reported-by: Roland Kletzing <devzero@web.de>
Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>

diff --git a/qm.adoc b/qm.adoc
index 900ecaeefe0e951049175dfb6577fcb301475825..c3e876f0ba29f88ebb3ceec89e545aef441aa638 100644 (file)
--- a/qm.adoc
+++ b/qm.adoc
@@ -253,7 +253,9 @@ The option *IO Thread* can only be used when using a disk with the *VirtIO*
 controller, or with the *SCSI* controller, when the emulated controller type is
 *VirtIO SCSI single*. With *IO Thread* enabled, QEMU creates one I/O thread per
 storage controller, rather than handling all I/O in the main event loop or vCPU
-threads. This can increase performance, because of improved work distribution.
+threads. This can increase performance, because of improved work distribution
+and also avoid hangs under very I/O-intensive host workloads, because other
+threads won't be blocked waiting for I/O.
 
 
 [[qm_cpu]]