Subject: Re: [RFC PATCH net-next 4/4 V4] try to fix performance regression

From: Weiping Pan <[email-masked]>
Date: Thu, 13 Dec 2012 22:09:12 +0800

On 12/13/2012 12:25 AM, Eric Dumazet wrote:
> On Wed, 2012-12-12 at 22:29 +0800, Weiping Pan wrote:
>
>>          MS       BASE    AF_UNIX    FRIENDS            TCP_STREAM_MS
>>           1      10.70       5.40       4.02   37%   74%
>>           2      28.01       9.67       7.97   28%   82%
>>           4      55.53      19.78      16.48   29%   83%
>>           8     115.40      38.22      33.51   29%   87%
>>          16     227.31      81.06      67.70   29%   83%
>>          32     446.20     166.59     129.31   28%   77%
>>          64     849.04     336.77     259.43   30%   77%
>>         128    1440.50     661.88     530.43   36%   80%
>>         256    2404.70    1279.67    1029.15   42%   80%
>>         512    4331.53    2501.30    1942.21   44%   77%
>>        1024    6819.78    4622.37    4128.10   60%   89%
>>        2048   10544.60    6348.81    6349.59   60%  100%
>>        4096   12830.41    8324.43    7984.43   62%   95%
>>        8192   13462.65    8355.49   11079.37   82%  132%
>>       16384    9960.87   10840.13   13037.81  130%  120%
>>       32768    8749.31   11372.15   15087.08  172%  132%
>>       65536    7580.27   12150.23   14971.42  197%  123%
>>      131072    6727.74   11451.34   13604.78  202%  118%
>>      262144    7673.14   11613.10   11436.97  149%   98%
>>      524288    7366.17   11675.95   11559.43  156%   99%
>>     1048576    6608.57   11883.01   10103.20  152%   85%
>> MS means Message Size in bytes, that is -m -M for netperf
> I cant reproduce your strange numbers here, they make no sense to me.
>
> for s in 1 2 4 8 16 32 64 128 256 512 1024 2048 4096 8192 16384 32768
> 65536 131072 262144 524288 1048576
> do
>   ./netperf -- -m $s -M $s | tail -n1
> done
>
> Results :
>
> 87380  16384      1    10.00      34.68
>   87380  16384      2    10.00      68.07
>   87380  16384      4    10.00     126.27
>   87380  16384      8    10.00     284.50
>   87380  16384     16    10.00     574.38
>   87380  16384     32    10.00    1091.74
>   87380  16384     64    10.00    2130.23
>   87380  16384    128    10.00    4001.83
>   87380  16384    256    10.00    7666.01
>   87380  16384    512    10.00    13425.81
>   87380  16384   1024    10.00    21146.43
>   87380  16384   2048    10.00    28551.42
>   87380  16384   4096    10.00    37878.95
>   87380  16384   8192    10.00    42507.23
>   87380  16384  16384    10.00    46782.53
>   87380  16384  32768    10.00    42410.97
>   87380  16384  65536    10.00    43053.09
>   87380  16384 131072    10.00    44504.20
>   87380  16384 262144    10.00    50211.74
>   87380  16384 524288    10.00    54004.23
>   87380  16384 1048576    10.00    53852.26
>
>
>
Hi, Eric,

In my test program, I run normal tcp loopback then friends for each 
message size,
then it generates such strange numbers.

But if I just run normal tcp loopback for each message size, then the 
performance is stable.

Maybe I should make the environment clean before each test, like 
dropping cache.

thanks
Weiping Pan