Red Hat Bugzilla – Bug 498242
QEMU threads should share the same I/O context
Last modified: 2011-06-27 10:11:11 EDT
Description of problem:
We want to use ionice to control QEMU's I/O priority per process. By default (I believe) each thread will get separate I/O context, so we need to set CLONE_IO for each thread QEMU spawns, so the entire process shares an I/O context.
Version-Release number of selected component (if applicable):
Steps to Reproduce:
what happens, then, to people who want to do per-thread/vcpu prioritization?
Can't we default to the current scheme, and then group the threads via cgroups or something like it?
Does it make any sense to do I/O prioritization on a per-thread/vcpu basis though ? It doesn't seem like you would/could associate I/O ops on a per guest vcpu basis ? And AFAIK, taking the CLONE_IO approach doesn't prevent CPU scheduler prioritization of individuals vCPU/threads.
This package has changed ownership in the Fedora Package Database. Reassigning to the new owner of this component.
Note: bug #509702 is requesting support for CLONE_IO in glibc; Uli suggests that it might make sense for CLONE_IO to be the default
Further update in bug #509702 - Uli suggests that this should a process-wide attribute configurable with prctl()
Is this still needed?
This bug appears to have been reported against 'rawhide' during the Fedora 13 development cycle.
Changing version to '13'.
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