From: Eric Dumazet <eric.dumazet@gmail.com>
To: Li Yu <raise.sail@gmail.com>
Cc: Linux Netdev List <netdev@vger.kernel.org>
Subject: Re: [RFC][PATCH 1/4] skbtrace: core feature
Date: Wed, 11 Jul 2012 08:32:03 +0200 [thread overview]
Message-ID: <1341988323.3265.6968.camel@edumazet-glaptop> (raw)
In-Reply-To: <4FFD1A0C.8090909@gmail.com>
On Wed, 2012-07-11 at 14:15 +0800, Li Yu wrote:
> 于 2012年07月11日 12:03, Eric Dumazet 写道:
> > You said that some 'buggy' drivers set rxhash to zero, but its a valid
> > operation.
> >
> > You said 'it seems that RPS hashing can not work well for some corner
> > cases', but its a known fact.
> >
>
> Em, we really are able to verify RPS imbalance by checking the last
> column of /proc/net/softnet_stat, but skbtrace can give us more details
> of RSS/RPS hashing. For improper RPS hashing case, it can provide more
> details of what really happen in real time.
A hash is a hash. Its rarely perfect.
RPS is a best effort, and not suitable for all needs.
If you follow netdev, maybe you saw that I suggested to use a BPF to
compute the hash, for specialized needs.
Of course, RFS can also help right now.
next prev parent reply other threads:[~2012-07-11 6:32 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-07-10 6:07 [RFC] skbtrace: A trace infrastructure for networking subsystem Li Yu
2012-07-11 2:17 ` [RFC][PATCH 1/4] skbtrace: core feature Li Yu
2012-07-11 4:03 ` Eric Dumazet
2012-07-11 6:15 ` Li Yu
2012-07-11 6:32 ` Eric Dumazet [this message]
2012-07-11 2:17 ` [RFC][PATCH 2/4] skbtrace: common code for skbtrace traces and skb_rps_info tracepoint Li Yu
2012-07-11 2:17 ` [RFC][PATCH 3/4] skbtrace: TCP/IP family support Li Yu
2012-07-11 2:18 ` [RFC][PATCH 4/4] skbtrace: four TCP/IP tracepoints tcp/icsk_connection,tcp_sendlim,tcp_congestion Li Yu
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