Messages in this thread | | | Subject | Re: [PATCH RFC 1/2] virtio-net: bql support | From | Jason Wang <> | Date | Wed, 2 Jan 2019 11:30:11 +0800 |
| |
On 2018/12/31 上午2:48, Michael S. Tsirkin wrote: > On Thu, Dec 27, 2018 at 06:04:53PM +0800, Jason Wang wrote: >> On 2018/12/26 下午11:22, Michael S. Tsirkin wrote: >>> On Thu, Dec 06, 2018 at 04:17:36PM +0800, Jason Wang wrote: >>>> On 2018/12/6 上午6:54, Michael S. Tsirkin wrote: >>>>> When use_napi is set, let's enable BQLs. Note: some of the issues are >>>>> similar to wifi. It's worth considering whether something similar to >>>>> commit 36148c2bbfbe ("mac80211: Adjust TSQ pacing shift") might be >>>>> benefitial. >>>> I've played a similar patch several days before. The tricky part is the mode >>>> switching between napi and no napi. We should make sure when the packet is >>>> sent and trakced by BQL, it should be consumed by BQL as well. >>> I just went over the patch again and I don't understand this comment. >>> This patch only enabled BQL with tx napi. >>> >>> Thus there's no mode switching. >>> >>> What did I miss? >> Consider the case: >> >> >> TX NAPI is disabled: >> >> send N packets >> >> turn TX NAPI on: >> >> get tx interrupt >> >> BQL try to consume those packets when lead WARN for dql. >> >> >> Thanks > Can one really switch tx napi on and off? How? > While root can change the napi_tx module parameter, I don't think > that has any effect outside device probe time. What did I miss? > > >
We support switch the mode through ethtool recently. See
commit 0c465be183c7c57a26446df6ea96d8676b865f92 Author: Jason Wang <jasowang@redhat.com> Date: Tue Oct 9 10:06:26 2018 +0800
virtio_net: ethtool tx napi configuration
Implement ethtool .set_coalesce (-C) and .get_coalesce (-c) handlers. Interrupt moderation is currently not supported, so these accept and display the default settings of 0 usec and 1 frame.
Toggle tx napi through setting tx-frames. So as to not interfere with possible future interrupt moderation, value 1 means tx napi while value 0 means not.
Only allow the switching when device is down for simplicity.
Link: https://patchwork.ozlabs.org/patch/948149/ Suggested-by: Jason Wang <jasowang@redhat.com> Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Jason Wang <jasowang@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Thanks
| |