Messages in this thread | | | From | Haiyang Zhang <> | Subject | RE: [Patch v3] net: mana: Batch ringing RX queue doorbell on receiving packets | Date | Thu, 29 Jun 2023 16:53:42 +0000 |
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> -----Original Message----- > From: Paolo Abeni <pabeni@redhat.com> > Sent: Thursday, June 29, 2023 4:43 AM > To: longli@linuxonhyperv.com; Jason Gunthorpe <jgg@ziepe.ca>; Leon > Romanovsky <leon@kernel.org>; Ajay Sharma <sharmaajay@microsoft.com>; > Dexuan Cui <decui@microsoft.com>; KY Srinivasan <kys@microsoft.com>; > Haiyang Zhang <haiyangz@microsoft.com>; Wei Liu <wei.liu@kernel.org>; > David S. Miller <davem@davemloft.net>; Eric Dumazet > <edumazet@google.com>; Jakub Kicinski <kuba@kernel.org> > Cc: linux-rdma@vger.kernel.org; linux-hyperv@vger.kernel.org; > netdev@vger.kernel.org; linux-kernel@vger.kernel.org; Long Li > <longli@microsoft.com>; stable@vger.kernel.org > Subject: Re: [Patch v3] net: mana: Batch ringing RX queue doorbell on receiving > packets > > On Mon, 2023-06-26 at 16:57 -0700, longli@linuxonhyperv.com wrote: > > From: Long Li <longli@microsoft.com> > > > > It's inefficient to ring the doorbell page every time a WQE is posted to > > the received queue. Excessive MMIO writes result in CPU spending more > > time waiting on LOCK instructions (atomic operations), resulting in > > poor scaling performance. > > > > Move the code for ringing doorbell page to where after we have posted all > > WQEs to the receive queue during a callback from napi_poll(). > > > > With this change, tests showed an improvement from 120G/s to 160G/s on a > > 200G physical link, with 16 or 32 hardware queues. > > > > Tests showed no regression in network latency benchmarks on single > > connection. > > > > While we are making changes in this code path, change the code for > > ringing doorbell to set the WQE_COUNT to 0 for Receive Queue. The > > hardware specification specifies that it should set to 0. Although > > currently the hardware doesn't enforce the check, in the future releases > > it may do. > > > > Cc: stable@vger.kernel.org > > Fixes: ca9c54d2d6a5 ("net: mana: Add a driver for Microsoft Azure Network > Adapter (MANA)") > > Uhmmm... this looks like a performance improvement to me, more suitable > for the net-next tree ?!? (Note that net-next is closed now).
This web page shows the net-next is "open": http://vger.kernel.org/~davem/net-next.html
Is this still the right place to check net-next status?
- Haiyang
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