From: "Michael S. Tsirkin" <mst@redhat•com>
To: Eric Dumazet <eric.dumazet@gmail•com>
Cc: Jason Wang <jasowang@redhat•com>,
davem@davemloft•net, hkchu@google•com,
netdev <netdev@vger•kernel.org>,
dwmw2@infradead•org
Subject: Re: [PATCH net-next] net: allow large number of tx queues
Date: Sun, 23 Jun 2013 13:29:51 +0300 [thread overview]
Message-ID: <20130623102951.GC17316@redhat.com> (raw)
In-Reply-To: <1371798750.3252.431.camel@edumazet-glaptop>
On Fri, Jun 21, 2013 at 12:12:30AM -0700, Eric Dumazet wrote:
> On Fri, 2013-06-21 at 14:41 +0800, Jason Wang wrote:
>
> > 1K queues (about 80 pages) looks a little bit aggressive which means we
> > may always fall back to vmalloc()?
>
> 1K queues looks like you should use 0 queue (LLTX) in fact, so that you
> design the minimal percpu structure in the driver to fit the needs.
>
> Using Qdisc, qith MQ, pfifo_fast, on 1000 'queues' is adding a fair
> amount of overhead and memory usage.
>
> For example, loopback driver only needs small percpu structure (16
> bytes), as it immediately forward the packet into netif_rx() [ Which
> also use a percpu area called softnet_data ]
>
>
I agree it's worth considering for tun.
But the same number of queues will be there for virtio net,
and that's much more like a regular network device.
--
MST
next prev parent reply other threads:[~2013-06-23 10:29 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-19 5:40 [net-next rfc 0/3] increase the limit of tuntap queues Jason Wang
2013-06-19 5:40 ` [net-next rfc 1/3] net: avoid high order memory allocation for queues by using flex array Jason Wang
2013-06-19 6:31 ` Eric Dumazet
2013-06-19 7:14 ` Jason Wang
2013-06-19 9:11 ` Michael S. Tsirkin
2013-06-19 9:56 ` Eric Dumazet
2013-06-19 12:22 ` Michael S. Tsirkin
2013-06-19 15:40 ` Michael S. Tsirkin
2013-06-19 15:58 ` Eric Dumazet
2013-06-19 16:06 ` David Laight
2013-06-19 16:28 ` Eric Dumazet
2013-06-19 18:07 ` Michael S. Tsirkin
2013-06-20 8:15 ` [PATCH net-next] net: allow large number of tx queues Eric Dumazet
2013-06-20 8:35 ` Michael S. Tsirkin
2013-06-21 6:41 ` Jason Wang
2013-06-21 7:12 ` Eric Dumazet
2013-06-23 10:29 ` Michael S. Tsirkin [this message]
2013-06-24 6:57 ` David Miller
2013-06-20 5:14 ` [net-next rfc 1/3] net: avoid high order memory allocation for queues by using flex array Jason Wang
2013-06-20 6:05 ` Eric Dumazet
2013-06-19 5:40 ` [net-next rfc 2/3] tuntap: reduce the size of tun_struct " Jason Wang
2013-06-19 5:40 ` [net-next rfc 3/3] tuntap: increase the max queues to 16 Jason Wang
2013-06-19 6:34 ` Eric Dumazet
2013-06-19 7:15 ` Jason Wang
2013-06-19 19:16 ` Jerry Chu
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