Messages in this thread | | | Date | Tue, 15 Jan 2008 10:09:09 -0500 | From | Vlad Yasevich <> | Subject | Re: questions on NAPI processing latency and dropped network packets |
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Chris Friesen wrote: > Eric Dumazet wrote: >> Chris Friesen a écrit : > >>> Based on the profiling information we're spending time in >>> sctp_endpoint_lookup_assoc() which doesn't actually use hashes, so I >>> can't see how the hash would be related. I'm pretty new to SCTP >>> though, so I may be missing something. >> >> Well, it does use hashes :) >> >> hash = sctp_assoc_hashfn(ep->base.bind_addr.port, rport); >> head = &sctp_assoc_hashtable[hash]; >> read_lock(&head->lock); >> sctp_for_each_hentry(epb, node, &head->chain) { >> /* maybe your machine is traversing here a *really* long >> chain */ >> } > > > The latest released kernel doesn't have this code, it was only added in > November. The SCTP maintainer just pointed me to the patch, and made > some other suggestions as well. >
Yes, the hash code only got added to 2.6.24. Before that, it was a linear list traversal which sucked.
I need to take a look at the locking to see if we can further reduce the time that bottom half is disabled.
-vlad -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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