testing using multiple threads

[ktechie]

I was doing a test of memcached using Contiperf to test by applying
load.
The memcached was populated with Strings as key and value
The keys would be "key_01" value is like "value_01".

The test involved only getting these values iteratively & second test
involved using multiget.

There was a tremendous improvement of using multiget over getting
iteratively.

However one more observation was that, as the number of threads
increased, the performance degradation was also very high.
Since I was doing only get operations, I am not sure why the
performance was degrading in multiples when the threads were
increasing.

We are facing some contention & performance issues, & thats why I ran
this test.

Need some help in understanding if this behaviour is expected or is
there anything I need to do.

[dennis zhuang]

How many threads did you test?Please offer more information about configuration and result.

2011/11/18 ktechie <kirandos...@gmail.com>

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庄晓丹
Email:        killm...@gmail.com
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淘宝（中国）软件有限公司 / 产品技术部 / Java中间件

[ktechie]

The Key was of the form "key_xx" and value was "value_xx".

I did the test with multiple combinations.
Find the data in csv files with the headings as below.

No of elements,"No of Memcached
Servers",Threads,Iterations,Iterative/Multi,Average Time(ms)

The values are :

100,1,1,10,I,36
100,1,1,10,M,6
100,1,5,10,I,112
100,1,5,10,M,26
100,1,10,10,I,215
100,1,10,10,M,42
500,1,1,10,I,101
500,1,1,10,M,6.5
500,1,5,10,I,349
500,1,5,10,M,33.5
500,1,10,10,I,697
500,1,10,10,M,52
1000,1,1,10,I,203
1000,1,1,10,M,9
1000,1,5,10,I,474
1000,1,5,10,M,34
1000,1,10,10,I,1128
1000,1,10,10,M,75.5
5000,1,10,10,I,5746
5000,1,10,10,M,318
5000,2,10,10,I,6011
5000,2,10,10,M,313
5000,4,10,10,I,6731
5000,4,10,10,M,293
5000,5,10,10,I,6390
5000,5,10,10,M,287
5000,5,1000,20,I,12162
5000,5,1000,20,M,431

In case this is not clear let me know

On Nov 18, 7:36 pm, dennis zhuang <killme2...@gmail.com> wrote:
> How many threads did you test?Please offer more information about
> configuration and result.
>

> 2011/11/18 ktechie <kirandoshitec...@gmail.com>
>
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On Nov 18, 7:36 pm, dennis zhuang <killme2...@gmail.com> wrote:
> How many threads did you test?Please offer more information about
> configuration and result.
>

> 2011/11/18 ktechie <kirandoshitec...@gmail.com>

> Email: killme2...@gmail.com

[dennis]

Hi,did you mean you test multi-fetch with 1000 threads? And the
performance degraded.

I think in this situation,you must try to use a connection
pool,because the xmemcached use a single connection by default.In the
high concurrent enviroment,the network IO may be a bottleneck.

[ktechie]

No it is in following order

No of elements,No of Memcached
Servers,Threads,Iterations,Iterative/Multi,Average Time(ms)

eg : 100,1,1,10,I,36 means
100 elements, 1 Memcached server, 1 Thread, 10 iterations, I -
Iterative, 36ms is average time.

The last two entries are in wrong order
It is 1000 iterations and 20 threads.

Sorry about that...

btw I am using a connection pool of 10.

[dennis zhuang]

How many elements did you multi-fetch at one time?

Email:        killm...@gmail.com

[ktechie]

I fetched all the elements together.

On Nov 25, 8:12 am, dennis zhuang <killme2...@gmail.com> wrote:
> How many elements did you multi-fetch at one time?
>