From: Jakub Kicinski <kuba@kernel.org>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Stephen Hemminger <stephen@networkplumber.org>,
Dave Taht <dave.taht@gmail.com>,
Willem de Bruijn <willemdebruijn.kernel@gmail.com>,
"Michael S. Tsirkin" <mst@redhat.com>,
Xianting Tian <xianting.tian@linux.alibaba.com>,
Linux Kernel Network Developers <netdev@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
virtualization <virtualization@lists.linux-foundation.org>,
bloat <bloat@lists.bufferbloat.net>,
"David S. Miller" <davem@davemloft.net>
Subject: Re: [Bloat] virtio_net: BQL?
Date: Wed, 19 May 2021 15:53:54 -0700 [thread overview]
Message-ID: <20210519155354.4438565e@kicinski-fedora-PC1C0HJN> (raw)
In-Reply-To: <a11eee78-b2a1-3dbc-4821-b5f4bfaae819@gmail.com>
On Wed, 19 May 2021 16:31:10 +0200 Eric Dumazet wrote:
> On 5/18/21 1:00 AM, Stephen Hemminger wrote:
> > The Azure network driver (netvsc) also does not have BQL. Several years ago
> > I tried adding it but it benchmarked worse and there is the added complexity
> > of handling the accelerated networking VF path.
>
> Note that NIC with many TX queues make BQL almost useless, only adding extra
> overhead.
>
> We should probably make BQL something that can be manually turned on/off.
Ah, I've been pondering this. Are you thinking of a bit in
dev_queue->state? Not perfect, because with a careful driver design
one can avoid most dev_queue accesses from the completion path.
It's still much better than recompiling the kernel to set BQL=n, tho.
next prev parent reply other threads:[~2021-05-19 22:53 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <56270996-33a6-d71b-d935-452dad121df7@linux.alibaba.com>
[not found] ` <CAA93jw6LUAnWZj0b5FvefpDKUyd6cajCNLoJ6OKrwbu-V_ffrA@mail.gmail.com>
[not found] ` <CA+FuTSf0Af2RXEG=rCthNNEb5mwKTG37gpEBBZU16qKkvmF=qw@mail.gmail.com>
2021-05-17 21:48 ` Dave Taht
2021-05-17 23:00 ` Stephen Hemminger
2021-05-17 23:32 ` Dave Taht
2021-05-18 2:48 ` Stephen Hemminger
2021-05-19 14:31 ` Eric Dumazet
2021-05-19 22:53 ` Jakub Kicinski [this message]
2021-05-24 2:53 ` Jason Wang
2021-05-24 9:10 ` Michael S. Tsirkin
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