On Sun, Mar 12, 2023 at 01:28:06PM +0000, Parav Pandit wrote: > > > > From: Michael S. Tsirkin <mst@xxxxxxxxxx> > > Sent: Sunday, March 12, 2023 6:25 AM > > > > On Sun, Mar 12, 2023 at 11:10:25AM +0200, Eli Cohen wrote: > > > > > > On 12/03/2023 10:58, Michael S. Tsirkin wrote: > > > > On Sun, Mar 12, 2023 at 10:39:19AM +0200, Eli Cohen wrote: > > > > > One can still enable it when creating the vdpa device using vdpa > > > > > tool by providing features that include it. > > > > > > > > > > For example: > > > > > $ vdpa dev add name vdpa0 mgmtdev pci/0000:86:00.2 device_features > > > > > 0x300cb982b > > > > > > > > > > Signed-off-by: Eli Cohen <elic@xxxxxxxxxx> > > > > What's the reason to turn it off by default? It's generally a > > > > performance win isn't it? > > > It has negative impact on packet rate so we want to keep it off by default. > > > The performance characteristics is very workload specific. > It is less of interest given the primary reason is backward compatibility, more below. > > > Interesting. I feel this would benefit from a bit more analysis. > > Packet rate with dpdk? With linux? Is there a chance this will regress some > > workloads? > > VIRTIO_NET_F_MRG_RXBUF was designed to save memory, which is good for > > small tcp buffers. > > Eli, > Please update the commit message. > This change is to avoid regression in existing systems. > The device previously didn't report MRG_RXBUF cap and it was not in use. > Lately, certain devices are reporting this feature bit and it is breaking the backward compatibility. > So the driver keeps it disabled by default. > User should enable it when user prefers to. OK. And which commit changes that? -- MST _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
