I had a small side-bar thread with Vitaly discussing the comprehensiveness of his measurements and how his tests are being conducted. He will report new results as they become available.
In the meantime, I stand behind that the patches need to be backported and there is a regression if we don't do that. Ubuntu has already provided a test kernel with the patches pulled in. I will test those as soon as I get the chance (hopefully by the end of the week). See: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1319003 Felipe > -----Original Message----- > From: Vitaly Kuznetsov [mailto:vkuzn...@redhat.com] > Sent: 20 May 2014 12:41 > To: Roger Pau Monne > Cc: Konrad Rzeszutek Wilk; ax...@kernel.dk; Felipe Franciosi; > gre...@linuxfoundation.org; linux-kernel@vger.kernel.org; > sta...@vger.kernel.org; jerry.snitsel...@oracle.com; xen- > de...@lists.xenproject.org > Subject: Re: [Xen-devel] Backport request to stable of two performance > related fixes for xen-blkfront (3.13 fixes to earlier trees) > > Roger Pau Monné <roger....@citrix.com> writes: > > > On 20/05/14 11:54, Vitaly Kuznetsov wrote: > >> Vitaly Kuznetsov <vkuzn...@redhat.com> writes: > >> > >>> 1) ramdisks (/dev/ram*) (persistent grants and indirect descriptors > >>> disabled) > >> > >> sorry, there was a typo. persistent grants and indirect descriptors > >> are enabled with ramdisks, otherwise such testing won't make any sense. > > > > I'm not sure how is that possible, from your description I get that > > you are using 3.11 on the Dom0, which means blkback has support for > > persistent grants and indirect descriptors, but the guest is RHEL7, > > that's using the 3.10 kernel AFAICT, and this kernel only has > > persistent grants implemented. > > RHEL7 kernel is mostly merged with 3.11 in its Xen part, we have indirect > descriptors backported. > > Actually I tried my tests with upstream (Fedora) kernel and results were > similar. I can try comparing e.g. 3.11.10 with 3.12.0 and provide exact > measurements. > > -- > Vitaly
