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From sebb <seb...@gmail.com>
Subject Re: HttpClient - use ConcurrentHashMap instead of HashMap?
Date Sun, 09 Jan 2011 19:06:20 GMT
On 9 January 2011 16:20, Ralph Goers <ralph.goers@dslextreme.com> wrote:
> Why did you post this to the commons dev list instead of http-components dev?

Oops, sorry!

However, the timings might still be interesting for Commons components...

> Ralph
>
> On Jan 9, 2011, at 7:32 AM, sebb wrote:
>
>> AbstractCookieSpec uses an unsynchronised  HashMap, so is not thread-safe.
>>
>> AIUI, ConcurrentHashMap has much better performance than a
>> synchronised HashMap - but of course we are not using synch here.
>>
>> A quick test using the code at [1] (1 thread, 1 VM) appears to show
>> that the performance of CHM and HM is fairly similar:
>>
>> Map type:           HashMap
>> Runtime:            3000
>> Number of threads:  1
>> Write probability:  0.6
>> Remove probability: 0.02
>> Ops per second:     1260837.0
>>
>> Map type:           ConcurrentHashMap
>> Runtime:            3000
>> Number of threads:  1
>> Write probability:  0.6
>> Remove probability: 0.02
>> Ops per second:     1313171.0
>>
>> So I wonder if we should consider replacing HashMap with
>> ConcurrentHashMap in Cookies and elsewhere in HttpClient?
>>
>> [1] http://unserializableone.blogspot.com/2007/04/performance-comparision-between.html
>>
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