That indeed provided a huge speed-up (0.5s compared to 1.5 originally).
Cheers Timothy

On Sunday, 1 December 2013 02:19:44 UTC+10:30, tbc++ wrote:
>
> There's several ways the performance of this code can be improved. 
>
> Firstly, these are exactly the same (samantically), but the latter is much 
> faster: (go (>! c v)) and (put! c v). Use put! whenever possible. 
>
> Secondly, the function "event" uses <!! (blocking take), but it's used 
> inside a go later on. Don't do this, it can cause issues in the go's fixed 
> thread pool. 
>
> I think you can also improve this code quite a bit by reducing the number 
> of puts/takes the system is doing. So consider changing this:
>
> (defn event [env type val]
>   (let [rc (async/chan)]
>     (async/<!!
>      (async/go
>       (async/>! (:queue @env)
>                 {:type type :val val :rc rc :time (:now @env)})
>       (async/<! rc)
>       (async/close! rc)))))
>
> (event ....)
>
> To this:
>
>
> (defn event [env type val]
>   (let [rc (async/chan)]
>      (*put!*
>
>       (:queue @env)
>
>       {:type type :val val :rc rc :time (:now @env)}))
>   rc))
>
> (<! (event ...))
>
> I have not benchmarked this new code, but it should run much faster. 
> Timothy
>
>
>
> On Fri, Nov 29, 2013 at 5:04 PM, kandre <andreas....@gmail.com<javascript:>
> > wrote:
>
>> Here is the gist: https://gist.github.com/anonymous/7713596
>> Please not that there's no ordering of time for this simple example and 
>> there's only one event (timeout). This is not what I intend to use but it 
>> shows the problem.
>> Simulating 10^5 steps this way takes ~1.5s
>>
>> Cheers
>> Andreas
>>
>> On Saturday, 30 November 2013 09:31:08 UTC+10:30, kandre wrote:
>>>
>>> I think I can provide you with a little code snipped. 
>>> I am talking about the very basic car example 
>>> (driving->parking->driving). Running the sim using core.async takes about 
>>> 1s for 10^5 steps whereas the simpy version takes less than 1s for 10^6 
>>> iterations on my vm.
>>> Cheers
>>> Andreas
>>>
>>> On Saturday, 30 November 2013 09:22:22 UTC+10:30, Ben Mabey wrote:
>>>>
>>>> On Fri Nov 29 14:13:16 2013, kandre wrote: 
>>>> > Thanks for all the replies. I accidentally left out the close! When I 
>>>> contrived the example. I am using core.async for a discrete event 
>>>> simulation system. There are hundreds of go blocks all doing little but 
>>>> putting a sequence of events onto 
>>>
>>>  
>>
>>> a channel and one go block advancing taking these events and advancing 
>>>> the time similar to simpy.readthedocs.org/ 
>>>> > 
>>>> > The basic one car example under the previous link executes about 10 
>>>> times faster than the same example using core.a sync. 
>>>> > 
>>>>
>>>> Hi Andreas, 
>>>> I've been using core.async for DES as well since I think the 
>>>> process-based approach is useful.  I could try doing the same 
>>>> simulation you're attempting to see how my approach compares 
>>>> speed-wise.  Are you talking about the car wash or the gas station 
>>>> simulation?  Posting a gist of what you have will be helpful so I can 
>>>> use the same parameters. 
>>>>
>>>> -Ben 
>>>>
>>>>
>>>>
>>>>
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>
>
> -- 
> “One of the main causes of the fall of the Roman Empire was that–lacking 
> zero–they had no way to indicate successful termination of their C 
> programs.”
> (Robert Firth) 
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