From: Rick Jones <rick.jones2@hp.com>
To: netdev <netdev@oss.sgi.com>
Subject: Re: [RFC] netif_rx: receive path optimization
Date: Thu, 31 Mar 2005 13:24:40 -0800 [thread overview]
Message-ID: <424C6A98.1070509@hp.com> (raw)
In-Reply-To: <1112303431.1073.67.camel@jzny.localdomain>
> The repurcassions of going from per-CPU-for-all-devices queue
> (introduced by softnet) to per-device-for-all-CPUs maybe huge in my
> opinion especially in SMP. A closer view of whats there now maybe
> per-device-per-CPU backlog queue.
> I think performance will be impacted in all devices. imo, whatever needs
> to go in needs to have some experimental data to back it
Indeed.
At the risk of again chewing on my toes (yum), if multiple CPUs are pulling
packets from the per-device queue there will be packet reordering. HP-UX 10.0
did just that and it was quite nasty even at low CPU counts (<=4). It was
changed by HP-UX 10.20 (ca 1995) to per-CPU queues with queue selection computed
from packet headers (hash the IP and TCP/UDP header to pick a CPU) It was called
IPS for Inbound Packet Scheduling. 11.0 (ca 1998) later changed that to "find
where the connection last ran and queue to that CPU" That was called TOPS -
Thread Optimized Packet Scheduling.
fwiw,
rick jones
next prev parent reply other threads:[~2005-03-31 21:24 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-03-30 21:28 [PATCH] netif_rx: receive path optimization Stephen Hemminger
2005-03-30 21:57 ` jamal
2005-03-30 22:08 ` jamal
2005-03-30 23:53 ` Stephen Hemminger
2005-03-31 3:16 ` jamal
2005-03-31 20:04 ` [RFC] " Stephen Hemminger
2005-03-31 21:10 ` Jamal Hadi Salim
2005-03-31 21:17 ` Stephen Hemminger
2005-03-31 21:25 ` Jamal Hadi Salim
2005-03-31 21:43 ` Eric Lemoine
2005-03-31 22:02 ` Stephen Hemminger
2005-03-31 21:24 ` Rick Jones [this message]
2005-03-31 21:38 ` jamal
2005-03-31 22:42 ` Rick Jones
2005-03-31 23:03 ` Nivedita Singhvi
2005-03-31 23:28 ` Rick Jones
2005-04-01 0:10 ` Stephen Hemminger
2005-04-01 0:42 ` Rick Jones
2005-04-01 0:30 ` Nivedita Singhvi
2005-03-31 23:36 ` jamal
2005-04-01 0:07 ` Rick Jones
2005-04-01 1:17 ` jamal
2005-04-01 18:22 ` Rick Jones
2005-04-01 16:40 ` Andi Kleen
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