Re: [PATCH RFC 0/2] Packed ring for vhost
- Date: Wed, 14 Feb 2018 10:43:29 +0800
- From: Jason Wang <jasowang@xxxxxxxxxx>
- Subject: Re: [PATCH RFC 0/2] Packed ring for vhost
On 2018年02月14日 10:37, Jason Wang wrote:
This RFC implement a subset of packed ring which was described at
. The code were tested with pmd implement by Jens at
change was needed for pmd codes to kick virtqueue since it assumes a
busy polling backend.
Test were done between localhost and guest. Testpmd (rxonly) in guest
reports 2.4Mpps. Testpmd (txonly) repots about 2.1Mpps.
It's not a complete implemention, here's what were missed:
- Device Area
- Driver Area
- Descriptor indirection
- Zerocopy may not be functional
- Migration path is not tested
- Vhost devices except for net
- vIOMMU can not work (mainly because the metadata prefetch is not
- See FIXME/TODO in the codes for more details
- No batching or other optimizations were implemented
For a quick prototype, this series open code the tracking of warp
counter and descriptor index at net device. This will be addressed in
the future by:
- Move get_rx_bufs() from net.c to vhost.c
- Let vhost_get_vq_desc() returns vring_used_elem instad of head id
With the above, we can hide the internal (at least part of) vring
layout from specific device.
It's near spring festival in China, will probably reply after the holiday.