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From: Eric Dumazet <eric.dumazet@gmail.com>
To: Jason Wang <jasowang@redhat.com>
Cc: "Michael S. Tsirkin" <mst@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: Fri, 21 Jun 2013 00:12:30 -0700	[thread overview]
Message-ID: <1371798750.3252.431.camel@edumazet-glaptop> (raw)
In-Reply-To: <51C3F5AC.2090008@redhat.com>

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 ]

  reply	other threads:[~2013-06-21  7:12 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 [this message]
2013-06-23 10:29                       ` Michael S. Tsirkin
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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