Actually opening an issue is the best way to make sure this gets addressed:

https://github.com/JuliaLang/julia/issues?state=open


On Tue, Apr 1, 2014 at 11:44 AM, Freddy Chua <[email protected]> wrote:

> Alright, these are my timings are disabling gc
>
> before disabling gc
> each for loop takes 911.240040
> after disabling gc
> each for loop takes 30.351131
>
> around 30x improvement.... and if my loop run 10 times, it would have been
> a 300x improvement...
>
> I hope julia devs do consider improving the GC invocation...
>
> On Tuesday, April 1, 2014 11:28:44 PM UTC+8, Freddy Chua wrote:
>>
>> Alright, I am pretty certain that
>>
>> macro nogc(ex)
>>   quote
>>     try
>>       gc_disable()
>>       local val = $(esc(ex))
>>     finally
>>       gc_enable()
>>     end
>>     val
>>   end
>> end
>>
>> Does the trick...
>>
>> My program does an iterative "gradient descent", a kind of mathematical
>> optimisation algorithm. So I loop through a for loop multiple times. In
>> each loop, nothing gets created or destroyed, so GC is not needed at all.
>> It turns out that turning off GC improves the performance significantly,
>> probably 100x. This issue is serious, I wonder can there be a better way of
>> determining when to call GC. I guessed disabling GC manually is not the
>> intention of the compiler designers..
>>
>> On Tuesday, April 1, 2014 11:12:07 PM UTC+8, Freddy Chua wrote:
>>>
>>> I found this, https://groups.google.com/forum/#!searchin/julia-
>>> users/garbage/julia-users/6_XvoLBzN60/EHCrT46tIQYJ
>>>
>>> Might try to turn off GC and see whether performance improves, will
>>> update here later...
>>>
>>> On Tuesday, April 1, 2014 11:07:03 PM UTC+8, Stefan Karpinski wrote:
>>>>
>>>> This code doesn't seem to create a List, Nodes or insert them into a
>>>> Dict - it just walks over a preexisting linked list.
>>>>
>>>>
>>>> On Tue, Apr 1, 2014 at 10:59 AM, Freddy Chua <[email protected]> wrote:
>>>>
>>>>> A possible flaw I have is the circular dependency in the data
>>>>> structures between Bus_Stop and Edge.
>>>>>
>>>>
>>>>

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