Note: This is a public test instance of Red Hat Bugzilla. The data contained within is a snapshot of the live data so any changes you make will not be reflected in the production Bugzilla. Email is disabled so feel free to test any aspect of the site that you want. File any problems you find or give feedback at bugzilla.redhat.com.
Bug 1123555 - virtio-mmio is slooowwwww
Summary: virtio-mmio is slooowwwww
Keywords:
Status: CLOSED WONTFIX
Alias: None
Product: Fedora
Classification: Fedora
Component: qemu
Version: 22
Hardware: Unspecified
OS: Unspecified
unspecified
unspecified
Target Milestone: ---
Assignee: Fedora Virtualization Maintainers
QA Contact: Fedora Extras Quality Assurance
URL:
Whiteboard:
Depends On:
Blocks: TRACKER-bugs-affecting-libguestfs
TreeView+ depends on / blocked
 
Reported: 2014-07-26 11:55 UTC by Richard W.M. Jones
Modified: 2015-11-04 23:55 UTC (History)
11 users (show)

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Clone Of:
Environment:
Last Closed: 2015-11-04 23:55:11 UTC
Type: Bug
Embargoed:

Attachments (Terms of Use)

Description Richard W.M. Jones 2014-07-26 11:55:41 UTC 
Description of problem:

On x86-64 (laptop, Core i7):

virtio-serial upload rate:      200553666 bytes/sec (191 Mbytes/sec)
virtio-serial download rate:    818819252 bytes/sec (780 Mbytes/sec)
block device writes:            128171758 bytes/sec (122 Mbytes/sec)
block device reads:             135930402 bytes/sec (129 Mbytes/sec)

[I don't yet have a clear explanation for why guest->host
(download) transfers are so much faster than the other way,
but that's not important for this bug.]

On aarch64:

virtio-serial upload rate:      7273232 bytes/sec (6 Mbytes/sec)
virtio-serial download rate:    16629760 bytes/sec (15 Mbytes/sec)
block device writes:            13466009 bytes/sec (12 Mbytes/sec)
block device reads:             17699635 bytes/sec (16 Mbytes/sec)

Version-Release number of selected component (if applicable):

x86-64 test was using qemu-2.0.0-0.1.rc0.fc21.x86_64
aarch test was with upstream qemu from git

How reproducible:

100%

Steps to Reproduce:
1. I'm using this program:
https://github.com/libguestfs/libguestfs/blob/master/tests/qemu/qemu-speed-test.c
Comment 1 Paolo Bonzini 2014-12-10 11:12:52 UTC 
I suspect it's not virtio-mmio, but just KVM on ARM.
Comment 2 Jaroslav Reznik 2015-03-03 16:09:15 UTC 
This bug appears to have been reported against 'rawhide' during the Fedora 22 development cycle.
Changing version to '22'.

More information and reason for this action is here:
https://fedoraproject.org/wiki/Fedora_Program_Management/HouseKeeping/Fedora22
Comment 3 Cole Robinson 2015-11-04 23:55:11 UTC 
I doubt virtio-mmio is going to get any faster since all future work is looking at virtio-pci. So this bug isn't going to generate anything IMO
Note You need to log in before you can comment on or make changes to this bug.