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Zookeeper >> mail # dev >> Something about performance of Zookeeper


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Re: Something about performance of Zookeeper
How many outstanding requests do you have at a time, Qian? Only one?  
If so, you should instead have multiple outstanding. That is, you  
don't wait for the callback to issue a new request.

-Flavio

On Mar 9, 2011, at 3:44 AM, Qian Ye wrote:

> Hi Flavio, asynchronous calls doesn't perform better, here is some  
> results we've got,
>
> § 1 client server,1 process per client server,connect 1  
> zookeeper server,all reads:cpu:14%~15%,qps:3833,latency:
> 0.000261
> § 1 client server,1 process per client server,connect all 3  
> zookeeper server,all reads:cpu:14%~15%,qps:3832,latency:
> 0.000261
> § 1 client server,10 process per client server,connect all 3  
> zookeeper server,all reads,cpu:13%~20%,qps:14000-
> >12000,latency:0.000469
> § 1 client server,30 process per client server,connect all 3  
> zookeeper server,all reads,cpu:15%~20%,qps:14000-
> >10000,,latency:
> § 2 client server,30 process per client server,connect all 3  
> zookeeper server,all reads,cpu:15%~20%,qps:about  
> 11000,latency:
>
> It seems that the asynchronous calls perform even worse than the  
> synchronous calls.
>
>
> On Wed, Mar 9, 2011 at 12:29 AM, Flavio Junqueira <fpj@yahoo-
> inc.com> wrote:
> Hi Qian, If I understand your description correctly, you are using  
> synchronous calls. To get high throughput values, you need multiple  
> outstanding requests, so you will need to use asynchronous calls.
>
> -Flavio
>
> On Mar 8, 2011, at 5:16 PM, Qian Ye wrote:
>
>> P.S. 1 we use zookeeper 3.3.2
>> P.S. 2 all our testing process get data from the same znode. The  
>> size of
>> data on the znode is less than 1K.
>>
>> On Wed, Mar 9, 2011 at 12:08 AM, Qian Ye <[EMAIL PROTECTED]>  
>> wrote:
>>
>>> Hi all:
>>>
>>> These days my friend and I did some performance tests on  
>>> zookeeper. We
>>> found the performance of zookeeper is not as good as it is  
>>> described in the
>>> Zookeeper Overview (
>>> http://hadoop.apache.org/zookeeper/docs/r3.3.2/
>>> zookeeperOver.html) . In
>>> the Zookeeper Overview, the "ZooKeeper Throughput as the Read-
>>> Write Ratio
>>> Varies" shows that in a ensemble of 3 Zookeeper server, the  
>>> throughput can
>>> reach about 80000, if the requests are all reads. However, we  
>>> cannot get
>>> results like that in our performance test with the synchronized  
>>> interface,
>>> zkpython.
>>>
>>> Here is some of our test results:
>>> (3 zookeeper ensemble, 8 core CPU,  2.4GHZ, 16 RAM, Linux 2.6.9)
>>>
>>> § 1 client server,1 process per client server,connect 1  
>>> zookeeper
>>> server,all reads:cpu:8%~9%,qps:2208,latency���0.000453s
>>> § 1 client server,1 process per client server,connect all 3  
>>> zookeeper
>>> server,all reads:cpu:8%~9%,qps:2376.241573 ,latency:
>>> 0.000421s
>>> § 1 client server,1 process per client server,connect all 3  
>>> zookeeper
>>> server,all reads,cpu:10%~20%,qps��15600,latency:
>>> 0.000764s
>>> *§ 1 client server,30 process per client server,connect all 3  
>>> zookeeper
>>> server,all reads,cpu:10%~20%,qps��15200,latency:*
>>> *§ 2 client server,30 process **per client server**,connect  
>>> all 3
>>> zookeeper server,all reads,cpu:10%~20%,qps:
>>> 15800,latency:0.003487*
>>>
>>> qps means "query per second", that is throughput. The result shows  
>>> that
>>> when adding more client server, the utilization rate of CPU don't  
>>> increase,
>>> and the throughput don't increase much. It seems that the  
>>> throughput won't
>>> reach 80000, even if we add 28 more client servers to reach the  
>>> number you
>>> mentioned in the Zookeeper Overview.
>>>
>>> Maybe I've done the tests wrong. Is there any particular thing I  
>>> should pay
>>> attention to in this case? We set the max java heap size to 12GB  
>>> in our
>>> test.
>>>
>>> *Could you tell me the details about how you do the performance  
>>> test, from
>>> which you get the results showed in the Zookeeper Overview?*
>>>
>>> --
>>> With Regards!
>>>
>>> Ye, Qian
>>>
>>>
>>
>>
>> --
>> With Regards!
>>
>> Ye, Qian

flavio
junqueira

research scientist

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