Michael S. Tsirkin
2022-Sep-07 19:36 UTC
[PATCH v5 2/2] virtio-net: use mtu size as buffer length for big packets
On Wed, Sep 07, 2022 at 07:27:16PM +0000, Parav Pandit wrote:> > > From: Michael S. Tsirkin <mst at redhat.com> > > Sent: Wednesday, September 7, 2022 3:24 PM > > > > On Wed, Sep 07, 2022 at 07:18:06PM +0000, Parav Pandit wrote: > > > > > > > From: Michael S. Tsirkin <mst at redhat.com> > > > > Sent: Wednesday, September 7, 2022 3:12 PM > > > > > > > > Because of shallow queue of 16 entries deep. > > > > > > > > but why is the queue just 16 entries? > > > I explained the calculation in [1] about 16 entries. > > > > > > [1] > > > > > https://lore.kernel.org/netdev/PH0PR12MB54812EC7F4711C1EA4CAA119DC > > 419@ > > > PH0PR12MB5481.namprd12.prod.outlook.com/ > > > > > > > does the device not support indirect? > > > > > > > Yes, indirect feature bit is disabled on the device. > > > > OK that explains it. > > So can we proceed with v6 to contain > (a) updated commit message and > (b) function name change you suggested to drop _fields suffix?(c) replace mtu = 0 with sensibly not calling the function when mtu is unknown. And I'd like commit log to include results of perf testing - with indirect feature on - with mtu feature off just to make sure nothing breaks. -- MST
Michael S. Tsirkin
2022-Sep-07 19:37 UTC
[PATCH v5 2/2] virtio-net: use mtu size as buffer length for big packets
On Wed, Sep 07, 2022 at 03:36:16PM -0400, Michael S. Tsirkin wrote:> On Wed, Sep 07, 2022 at 07:27:16PM +0000, Parav Pandit wrote: > > > > > From: Michael S. Tsirkin <mst at redhat.com> > > > Sent: Wednesday, September 7, 2022 3:24 PM > > > > > > On Wed, Sep 07, 2022 at 07:18:06PM +0000, Parav Pandit wrote: > > > > > > > > > From: Michael S. Tsirkin <mst at redhat.com> > > > > > Sent: Wednesday, September 7, 2022 3:12 PM > > > > > > > > > > Because of shallow queue of 16 entries deep. > > > > > > > > > > but why is the queue just 16 entries? > > > > I explained the calculation in [1] about 16 entries. > > > > > > > > [1] > > > > > > > https://lore.kernel.org/netdev/PH0PR12MB54812EC7F4711C1EA4CAA119DC > > > 419@ > > > > PH0PR12MB5481.namprd12.prod.outlook.com/ > > > > > > > > > does the device not support indirect? > > > > > > > > > Yes, indirect feature bit is disabled on the device. > > > > > > OK that explains it. > > > > So can we proceed with v6 to contain > > (a) updated commit message and > > (b) function name change you suggested to drop _fields suffix? > > (c) replace mtu = 0 with sensibly not calling the function > when mtu is unknown. > > > And I'd like commit log to include results of perf testing > - with indirect feature on > - with mtu feature off > just to make sure nothing breaks.and if possible a larger ring. 1k?> -- > MST
Parav Pandit
2022-Sep-07 19:51 UTC
[PATCH v5 2/2] virtio-net: use mtu size as buffer length for big packets
> From: Michael S. Tsirkin <mst at redhat.com> > Sent: Wednesday, September 7, 2022 3:36 PM > > On Wed, Sep 07, 2022 at 07:27:16PM +0000, Parav Pandit wrote: > > > > > From: Michael S. Tsirkin <mst at redhat.com> > > > Sent: Wednesday, September 7, 2022 3:24 PM > > > > > > On Wed, Sep 07, 2022 at 07:18:06PM +0000, Parav Pandit wrote: > > > > > > > > > From: Michael S. Tsirkin <mst at redhat.com> > > > > > Sent: Wednesday, September 7, 2022 3:12 PM > > > > > > > > > > Because of shallow queue of 16 entries deep. > > > > > > > > > > but why is the queue just 16 entries? > > > > I explained the calculation in [1] about 16 entries. > > > > > > > > [1] > > > > > > > > https://lore.kernel.org/netdev/PH0PR12MB54812EC7F4711C1EA4CAA119DC > > > 419@ > > > > PH0PR12MB5481.namprd12.prod.outlook.com/ > > > > > > > > > does the device not support indirect? > > > > > > > > > Yes, indirect feature bit is disabled on the device. > > > > > > OK that explains it. > > > > So can we proceed with v6 to contain > > (a) updated commit message and > > (b) function name change you suggested to drop _fields suffix? > > (c) replace mtu = 0 with sensibly not calling the function when mtu is > unknown.> > > And I'd like commit log to include results of perf testing > - with indirect feature onWhich device do you suggest using for this test?> - with mtu feature offWhy is this needed when it is not touching the area of mtu being not offered?> just to make sure nothing breaks.Not sure why you demand this. Can you please share the link to other patches that ensured that nothing breaks, for example I didn't see a similar "test ask" in v14 series [1]? What is so special about current patch of interest vs [1] that requires this special testing details in commit log, and it is not required in [1] or past patches? Do you have link to the tests done with synchronization tests by commit [2]? This will help to define test matrix for developers and internal regression and similar report in all subsequent patches like [1]. [1] https://lore.kernel.org/bpf/20220801063902.129329-41-xuanzhuo at linux.alibaba.com/ [2] 6213f07cb54
Parav Pandit
2022-Sep-07 20:04 UTC
[PATCH v5 2/2] virtio-net: use mtu size as buffer length for big packets
> From: Michael S. Tsirkin <mst at redhat.com> > Sent: Wednesday, September 7, 2022 3:36 PM > > (c) replace mtu = 0 with sensibly not calling the function when mtu is > unknown.Even when mtu is zero, virtnet_set_big_packets() must be called to act on the gso bits. Currently handling by virtnet_set_big_packets() seems more simpler taking care of mtu and gso both.