netdev - Re: Fwd: [RFC v3] net: Introduce recvmmsg socket syscall

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <9b2db90b0909151120l71498303w26cfd657c9f18092@mail.gmail.com>
Date:	Tue, 15 Sep 2009 21:20:13 +0300
From:	Nir Tzachar <nir.tzachar@...il.com>
To:	Arnaldo Carvalho de Melo <acme@...stprotocols.net>
Cc:	Linux Networking Development Mailing List 
	<netdev@...r.kernel.org>, Ziv Ayalon <ziv@...al.co.il>
Subject: Re: Fwd: [RFC v3] net: Introduce recvmmsg socket syscall

>> Setup:
>> linux 2.6.29.2 with the third version of the patch, running on an
>> Intel Xeon X3220 2.4GHz quad core, with 4Gbyte of ram, running Ubuntu
>> 9.04
>
> Which NIC? 10 Gbit/s?

1G. We do not care as much for throughput as we do about latency...


>> Results:
>> On general, the recvmmsg beats the pants off the regular recvmsg by a
>> whole millisecond (which might not sound much, but is _really_ a lot
>> for us ;). The exact distribution fluctuates between half a milli and
>> 2 millis, but the average is 1 milli.
>
> Do you have any testcase using publicly available software? Like qpidd,
> etc? I'll eventually have to do that, for now I'm just using that
> recvmmsg tool I posted, now with a recvmsg mode, then collecting 'perf
> record' with and without callgraphs to post here. The client is just
> pktgen spitting datagrams as if there is no tomorrow :-)

No. This was on a live, production system.


> Showing that we get latency improvements is complementary to what I'm
> doing, that is for now just showing the performance improvements and
> showing what gives this improvement (perf counters runs).

We are more latency oriented, and, naturally, concentrate on this
aspect of the problem. Producing numbers here is much more easier....
I can easily come up with a test application which just measures the
latency of processing packets, by employing a sending loop between two
hosts.

> If you could come up with a testcase that you could share with us,
> perhaps using one of these AMQP implementations, that would be great
> too.

Well, in our experience, AMQP and other solutions have latency issues.
Moreover, the receiving end of our application is a regular multicast
stream. I will implement the simple latency test I mentioned earlier,
and post some results soon.

Nir.
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html