Re: kern/50604 (ld(4) on top of virtio(4) performs very badly)

[Matthias Scheler <tron%zhadum.org.uk@localhost>]

The following reply was made to PR kern/50604; it has been noted by GNATS.

From: Matthias Scheler <tron%zhadum.org.uk@localhost>
To: gnats-bugs%NetBSD.org@localhost
Cc: 
Subject: Re: kern/50604 (ld(4) on top of virtio(4) performs very badly)
Date: Wed, 30 Nov 2016 14:35:47 +0000

 On Wed, Nov 30, 2016 at 02:05:01AM +0000, Valery Ushakov wrote:
 >  The following might be related.  Please, can you test with this revision?
 >  
 >  On Tue, Nov 29, 2016 at 20:36:38 -0500, Christos Zoulas wrote:
 >  
 >  > Module Name:	src
 >  > Committed By:	christos
 >  > Date:		Wed Nov 30 01:36:38 UTC 2016
 >  > 
 >  > Modified Files:
 >  > 	src/sys/dev/pci: ld_virtio.c viornd.c
 >  > 
 >  > Log Message:
 >  > Don't call virtio_enqueue_abort when virtio_enqueue_reserve fails.
 >  > Pointed out by uwe@
 >  > 
 >  > 
 >  > To generate a diff of this commit:
 >  > cvs rdiff -u -r1.12 -r1.13 src/sys/dev/pci/ld_virtio.c
 >  > cvs rdiff -u -r1.9 -r1.10 src/sys/dev/pci/viornd.c
 
 I've tried with a "GENERIC" kernel built from 2016-11-30 08:00 UTC sources:
 
 	NetBSD lyssa.zhadum.org.uk 7.99.43 NetBSD 7.99.43 (GENERIC) #0: Wed Nov 30 10:22:36 GMT 2016  tron%lyssa.zhadum.org.uk@localhost:/src/sys/compile/GENERIC amd64
 
 I've used the exact same machine on the same HyperVisor. These are the
 only difference in the KVM machine configuration:
 
 --- lyssa-ide.xml	2016-11-30 14:20:33.928453288 +0000
 +++ lyssa-virtio.xml	2016-11-30 14:24:03.459133542 +0000
 @@ -9,6 +9,7 @@
    </resource>
    <os>
      <type arch='x86_64' machine='pc-i440fx-2.1'>hvm</type>
 +    <boot dev='hd'/>
    </os>
    <features>
      <acpi/>
 @@ -68,9 +69,8 @@
      <disk type='file' device='disk'>
        <driver name='qemu' type='qcow2'/>
        <source file='/var/lib/libvirt/images/lyssa.qcow2'/>
 -      <target dev='hda' bus='ide'/>
 -      <boot order='1'/>
 -      <address type='drive' controller='0' bus='0' target='0' unit='0'/>
 +      <target dev='vda' bus='virtio'/>
 +      <address type='pci' domain='0x0000' bus='0x00' slot='0x08' function='0x0'/>
      </disk>
      <disk type='block' device='cdrom'>
        <driver name='qemu' type='raw'/>
 
 Here are the result of my simple disk I/O benchmark:
 
 1.) Using IDE:
 	> time sh -c "tar -xzf /scratch/pkgsrc/distfiles/emacs-24.5.tar.gz && sync && rm -rf emacs-24.5 && sync"
 sh -c   0.90s user 1.29s system 12% cpu 17.144 total
 
 2.) Using VirtIO:
 	> time sh -c "tar -xzf /scratch/pkgsrc/distfiles/emacs-24.5.tar.gz && sync && rm -rf emacs-24.5 && sync"
 	sh -c   0.96s user 1.33s system 1% cpu 2:19.39 total
 
 So the problem still exists.
 
 	Kind regards
 
 -- 
 Matthias Scheler                                 https://zhadum.org.uk/