"Michael S. Tsirkin" <mst at redhat.com> writes:> Please dont' do this, extra indirection hurts performance. > Instead, please change vhost_net_open and scsi to allocate the whole > structure with vmalloc if kmalloc fails, along the lines of > 74d332c13b2148ae934ea94dac1745ae92efe8e5Back in January 2013, you didn't seem to think it was a good idea: https://lkml.org/lkml/2013/1/23/492
On Tue, 13 May 2014 16:29:58 +0200 Romain Francoise <romain at orebokech.com> wrote:> "Michael S. Tsirkin" <mst at redhat.com> writes: > > > Please dont' do this, extra indirection hurts performance. > > Instead, please change vhost_net_open and scsi to allocate the whole > > structure with vmalloc if kmalloc fails, along the lines of > > 74d332c13b2148ae934ea94dac1745ae92efe8e5 > > Back in January 2013, you didn't seem to think it was a good idea: > > https://lkml.org/lkml/2013/1/23/492 >Hi Romain, in that case I'd suggest that you submit your patch, ours will look pretty much the same! Cheers Michael
On Tue, May 13, 2014 at 04:29:58PM +0200, Romain Francoise wrote:> "Michael S. Tsirkin" <mst at redhat.com> writes: > > > Please dont' do this, extra indirection hurts performance. > > Instead, please change vhost_net_open and scsi to allocate the whole > > structure with vmalloc if kmalloc fails, along the lines of > > 74d332c13b2148ae934ea94dac1745ae92efe8e5 > > Back in January 2013, you didn't seem to think it was a good idea: > > https://lkml.org/lkml/2013/1/23/492Hmm true, and Dave thought the structure's too large. I'll have to do some benchmarks to see what the effect of Michael's patch is, performance-wise. If it's too expensive I can pick up your patch, no need to repost. -- MST
On Tue, 13 May 2014 18:15:27 +0300 "Michael S. Tsirkin" <mst at redhat.com> wrote:> On Tue, May 13, 2014 at 04:29:58PM +0200, Romain Francoise wrote: > > "Michael S. Tsirkin" <mst at redhat.com> writes: > > > > > Please dont' do this, extra indirection hurts performance. > > > Instead, please change vhost_net_open and scsi to allocate the whole > > > structure with vmalloc if kmalloc fails, along the lines of > > > 74d332c13b2148ae934ea94dac1745ae92efe8e5 > > > > Back in January 2013, you didn't seem to think it was a good idea: > > > > https://lkml.org/lkml/2013/1/23/492 > > Hmm true, and Dave thought the structure's too large. > I'll have to do some benchmarks to see what the effect > of Michael's patch is, performance-wise. > If it's too expensive I can pick up your patch, no need to > repost. >Thanks, let us know then.
On Tue, 13 May 2014 18:15:27 +0300 "Michael S. Tsirkin" <mst at redhat.com> wrote:> On Tue, May 13, 2014 at 04:29:58PM +0200, Romain Francoise wrote: > > "Michael S. Tsirkin" <mst at redhat.com> writes: > > > > > Please dont' do this, extra indirection hurts performance. > > > Instead, please change vhost_net_open and scsi to allocate the whole > > > structure with vmalloc if kmalloc fails, along the lines of > > > 74d332c13b2148ae934ea94dac1745ae92efe8e5 > > > > Back in January 2013, you didn't seem to think it was a good idea: > > > > https://lkml.org/lkml/2013/1/23/492 > > Hmm true, and Dave thought the structure's too large. > I'll have to do some benchmarks to see what the effect > of Michael's patch is, performance-wise. > If it's too expensive I can pick up your patch, no need to > repost. >Hi Michael, do you have any update in this case for us? Michael