Re: [PATCH net-next] softirq: reduce latencies
From: Eric Dumazet
Date: Thu Jan 03 2013 - 08:31:48 EST
On Thu, 2013-01-03 at 14:12 +0100, Sedat Dilek wrote:
> Hi Eric,
> your patch from  applies cleanly on top of Linux v3.8-rc2.
> I would like to test it.
> In  you were talking about benchmarks you did.
> Can you describe them or provide a testcase (script etc.)?
> You made only network testing?
Yes I did network testing :
- net_rx_action() softirq handler is the typical function that can
consume 2 ms per call.
I did some netperf sessions, with multiqueue 10G nics, tuned to that IRQ
would be handled by few cpus.
(check /proc/irq/*/eth0-$QUEUE/../smp_affinity )
Another way to make the softirq processing use more cpu cycles is by
adding a fake iptable setup like :
for n in `seq 1 100`
iptables -I INPUT
A common network load is to launch ~200 concurrent TCP_RR netperf
sessions like the following
netperf -H remote_host -t TCP_RR -l 1000
And then you can launch some netperf asking P99_LATENCY results :
netperf -H remote_host -t TCP_RR -- -k P99_LATENCY
You can play with taskset or netperf option -T to force
netperf/netserver running on given cpus.
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