Re: [PATCH net v4 1/2] net: sched: fix packet stuck problem for lockless qdisc

From: Yunsheng Lin <linyunsheng@huawei.com>
To: Michal Kubecek <mkubecek@suse.cz>
Cc: <davem@davemloft.net>, <kuba@kernel.org>, <olteanv@gmail.com>,
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	<linuxarm@openeuler.org>, <mkl@pengutronix.de>,
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	<hdanton@sina.com>, <jgross@suse.com>, <JKosina@suse.com>
Subject: Re: [PATCH net v4 1/2] net: sched: fix packet stuck problem for lockless qdisc
Date: Wed, 21 Apr 2021 17:25:06 +0800	[thread overview]
Message-ID: <b3dacf14-0fb6-0cad-8b85-f5c8d7cd97ef@huawei.com> (raw)
In-Reply-To: <20210421084428.xbjgoi4r2d6t65gy@lion.mk-sys.cz>

On 2021/4/21 16:44, Michal Kubecek wrote:
> On Wed, Apr 21, 2021 at 04:21:54PM +0800, Yunsheng Lin wrote:
>>
>> I tried using below shell to simulate your testcase:
>>
>> #!/bin/sh
>>
>> for((i=0; i<20; i++))
>> do
>>         taskset -c 0-31 netperf -t TCP_STREAM -H 192.168.100.2 -l 30 -- -m 1048576
>> done
>>
>> And I got a quite stable result: 9413~9416 (10^6bits/sec) for 10G netdev.
> 
> Perhaps try it without the taskset, in my test, there was only one
> connection.

Just tried, and got the similar result as above.

> 
>>>
>>>   https://github.com/mkubecek/nperf
>>>
>>> It is still raw and a lot of features are missing but it can be already
>>> used for multithreaded TCP_STREAM and TCP_RR tests. In particular, the
>>> output above was with
>>>
>>>   nperf -H 172.17.1.1 -l 30 -i 20 --exact -t TCP_STREAM -M 1
>>
>> I tried your nperf too, unfortunately it does not seem to work on my
>> system(arm64), which exits very quickly and output the blow result:
>>
>> root@(none):/home# nperf -H 192.168.100.2 -l 30 -i 20 --exact -t TCP_STREAM -M 1
>> server: 192.168.100.2, port 12543
>> iterations: 20, threads: 1, test length: 30
>> test: TCP_STREAM, message size: 1048576
>>
>> 1             4.0 B/s,  avg           4.0 B/s, mdev           0.0 B/s (  0.0%)
> [...]
> 
> Did you start nperfd on the other side? (It plays a role similar to
> netserver for netperf.) Few days ago I noticed that there is something
> wrong with error handling in case of failed connection but didn't get to
> fixing it yet.

Yes, I did. If I did not start nperfd, I got "connect: Connection refused"
as below:

nperf -H 192.168.100.2 -l 30 -i 20 --exact -t TCP_STREAM -M 1
server: 192.168.100.2, port 12543
iterations: 20, threads: 1, test length: 30
test: TCP_STREAM, message size: 1048576

connect: Connection refused
failed to connect to '192.168.100.2'
1             4.0 B/s,  avg           4.0 B/s, mdev           0.0 B/s (  0.0%)
connect: Connection refused
failed to connect to '192.168.100.2'
2             4.0 B/s,  avg           4.0 B/s, mdev           0.0 B/s (  0.0%), confid. +/-           0.0 B/s (  0.0%)
connect: Connection refused
failed to connect to '192.168.100.2'

> 
> I'll try running some tests also on other architectures, including arm64
> and s390x (to catch potential endinanity issues).
> 
> Michal
> 
> .
> 