From: Jesper Dangaard Brouer <brouer@redhat•com>
To: Eric Dumazet <eric.dumazet@gmail•com>
Cc: brouer@redhat•com,
"netdev@vger•kernel.org" <netdev@vger•kernel.org>,
"Stephen Hemminger" <stephen@networkplumber•org>,
"Tom Herbert" <therbert@google•com>,
"David Miller" <davem@davemloft•net>,
"Hannes Frederic Sowa" <hannes@stressinduktion•org>,
"Daniel Borkmann" <dborkman@redhat•com>,
"Florian Westphal" <fw@strlen•de>,
"Toke Høiland-Jørgensen" <toke@toke•dk>,
"Dave Taht" <dave.taht@gmail•com>
Subject: Qdisc: Measuring Head-of-Line blocking with netperf-wrapper
Date: Mon, 15 Sep 2014 18:45:17 +0200 [thread overview]
Message-ID: <20140915184517.6c5474e5@redhat.com> (raw)
Hi Eric,
I've constructed a "netperf-wrapper" test for measuring Head-of-Line
blocking, called "tcp_upload_prio", that I hope you will approve of?
https://github.com/tohojo/netperf-wrapper/commit/1e6b755e8051b6
The basic idea is to have ping packets with TOS bit 0x10, which end-up
in the high-prio band of pfifo_fast. While two TCP uploads utilize
all the bandwidth.
These high-prio ping packet should then demonstrate the Head-of-Line
blocking occurring due to 1) packets in the HW TX ring buffer, or
2) in the qdisc layers requeue mechanism. Disgusting these two case
might be a little difficult.
Special care need to be take for using this on the default
qdisc MQ which have pfifo_fast assigned for every HW queue.
Setup requirements:
1. IRQ align CPUs to NIC HW queues
2. Force netperf-wrapper subcommands to run the same CPU
E.g: taskset -c 2 ./netperf-wrapper -H IP tcp_upload_prio
This will force all measurements to go through the same qdisc. This
is needed so the ping/latency tests measures the real property of
the qdisc and Head-of-Line blocking effect.
Basically the same as:
sudo taskset -c 2 ping -Q 0x10 192.168.8.2
sudo taskset -c 2 ping 192.168.8.2
sudo taskset -c 2 netperf -H 192.168.8.2 -t TCP_STREAM -l 120
sudo taskset -c 2 netperf -H 192.168.8.2 -t TCP_STREAM -l 120
--
Best regards,
Jesper Dangaard Brouer
MSc.CS, Sr. Network Kernel Developer at Red Hat
Author of http://www.iptv-analyzer.org
LinkedIn: http://www.linkedin.com/in/brouer
next reply other threads:[~2014-09-15 16:46 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-15 16:45 Jesper Dangaard Brouer [this message]
2014-09-15 17:10 ` Qdisc: Measuring Head-of-Line blocking with netperf-wrapper Tom Herbert
2014-09-15 17:24 ` Eric Dumazet
2014-09-15 18:55 ` Dave Taht
2014-09-15 19:12 ` Rick Jones
2014-09-16 6:30 ` Jesper Dangaard Brouer
2014-09-16 15:52 ` Tom Herbert
2014-09-16 13:22 ` Jesper Dangaard Brouer
2014-09-16 13:59 ` Eric Dumazet
2014-09-16 15:56 ` Jesper Dangaard Brouer
2014-09-16 16:08 ` Dave Taht
2014-09-16 16:30 ` Eric Dumazet
2014-09-17 7:39 ` Jesper Dangaard Brouer
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