[LTP] [PATCH] busy_poll* : revise poll_cmp

[Alexey Kodanev]

On 22.03.2018 11:03, sunlianwen wrote:
> Hi Alexey
> 
> On 03/21/2018 06:50 PM, Alexey Kodanev wrote:
>> On 03/20/2018 03:18 AM, sunlianwen wrote:
>>> Hi Alexey
>>>
>>>   You are right, I think is wrong, I debug this case again,
>>>
>>> and find the driver is virtio_net no support busy poll.
>>
>> There is support in virtio_net... may be the problem in the underlying
>> configuration/driver, latency between guest and the other host? you could
>> also try netperf -H remote_host -t TCP_RR with/without busy_polling:
>>
>> # sysctl net.core.busy_read=50
>> # sysctl net.core.busy_poll=50
>>
> Thanks your advise. and I find a patch:"virtio_net: remove custom busy_poll"
> patch link :https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/drivers/net/virtio_net.c?id=ceef438d613f6d
> I am not sure  whether this patch  mean virtio_net no support busy poll.

It means it is using generic busy polling implementation now.

> 
> Below is debuginfo follow your advise.
> 
> # sysctl net.core.busy_read=0
> net.core.busy_read = 0
> 
> # sysctl net.core.busy_poll=0
> net.core.busy_poll = 0
> 
> # netperf -H 192.168.122.248 -t TCP_RR
> MIGRATED TCP REQUEST/RESPONSE TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.122.248 () port 0 AF_INET : first burst 0
> Local /Remote
> Socket Size   Request  Resp.   Elapsed  Trans.
> Send   Recv   Size     Size    Time     Rate
> bytes  Bytes  bytes    bytes   secs.    per sec
> 
> 16384  87380  1        1       10.00    30101.63
> 16384  87380
> 
> # sysctl net.core.busy_read=50
> net.core.busy_read = 50
> # sysctl net.core.busy_poll=50
> net.core.busy_poll = 50
> 
> # netperf -H 192.168.122.248 -t TCP_RR
> MIGRATED TCP REQUEST/RESPONSE TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.122.248 () port 0 AF_INET : first burst 0
> Local /Remote
> Socket Size   Request  Resp.   Elapsed  Trans.
> Send   Recv   Size     Size    Time     Rate
> bytes  Bytes  bytes    bytes   secs.    per sec
> 
> 16384  87380  1        1       10.00    37968.90
> 16384  87380
> 

Looks like busy polling is working, transaction rate is obviously faster
than without busy polling.

> -----------------------------------------------------------------------
> <<<test_output>>>
> incrementing stop
> busy_poll01 1 TINFO: Network config (local -- remote):
> busy_poll01 1 TINFO: eth1 -- eth1
> busy_poll01 1 TINFO: 192.168.1.41/24 -- 192.168.1.20/24

You run netperf with 192.168.122.248 server, LTP using the other hosts?
Could you check netperf and LTP for the same hosts/interfaces?


> busy_poll01 1 TINFO: fd00:1:1:1::1/64 -- fd00:1:1:1::2/6> busy_poll01 1 TINFO: set low latency busy poll to 50
> busy_poll01 1 TINFO: run server 'netstress -R 500000 -B /tmp/ltp-EmybkMxKgu/busy_poll01.IIOgfKYQ6P'
> busy_poll01 1 TINFO: run client 'netstress -l -H 192.168.1.20 -a 2 -r 500000 -d res_50 -g 44175'
> busy_poll01 1 TPASS: netstress passed, time spent '53265' ms
> busy_poll01 2 TINFO: set low latency busy poll to 0
> busy_poll01 2 TINFO: run server 'netstress -R 500000 -B /tmp/ltp-EmybkMxKgu/busy_poll01.IIOgfKYQ6P'
> busy_poll01 2 TINFO: run client 'netstress -l -H 192.168.1.20 -a 2 -r 500000 -d res_0 -g 46767'
> busy_poll01 2 TPASS: netstress passed, time spent '23393' ms
> busy_poll01 3 TFAIL: busy poll result is '-127' %
> <<<execution_status>>>
> initiation_status="ok"
> duration=79 termination_type=exited termination_id=1 corefile=no
> cutime=148 cstime=6930
> <<<test_end>>>
> INFO: ltp-pan reported some tests FAIL
> LTP Version: 20180118
> 
>        ###############################################################
> 
>             Done executing testcases.
>             LTP Version:  20180118
>        ###############################################################
> 
> Thanks,
> Lianwen Sun