On Sat, Jan 10, 2015 at 9:01 PM, <t...@wakelift.de> wrote:
>
> On 01/10/2015 07:53 PM, Gabor Szabo wrote:
>
> On Sat, Jan 10, 2015 at 7:57 PM, <t...@wakelift.de> wrote:
>
>> That happens because the result of the for statement is a list that is
>> then sunk; it contains one scalar and one Int object for each iteration
>> and rakudo doesn't yet know to throw it away immediately.
>>
>
> The problem happens even without the internal $x variable, but my main
> problem
> is that this means the web application running the Perl6Maven.com site
> fills the memory
> after just a few requests.
>
> A quick check seems to indicated that while-loops don't have the same
> memory leak,
> but before I run and rewrite every for loop into a while-loop, it would be
> nice to know
> if there are other parts of the language that are leaking memory?
>
>
> regards
> Gabor
>
>
> Fortunately, it's not as bad as you think. Compare these two invocations:
>
> time perl6 -e 'for ^1000 { for ^1000 { }; 1 }'
> 0.91user 0.02system 0:00.94elapsed 99%CPU (0avgtext+0avgdata
> 113448maxresident)k
>
> time perl6 -e 'for ^1000 { for ^10000 { }; 1 }'
> 5.53user 0.02system 0:05.59elapsed 99%CPU (0avgtext+0avgdata
> 114744maxresident)k
>
>
> The MaxRSS hardly differs, because the list that belongs to the inner for
> loop gets garbage collected properly.
>
> There isn't an actual memory leak, it's just that the result of the for
> loop is (wrongly) being kept around.
>
> There was also an optimization that turns a for ^1000 loop into a while
> loop with a native counter for great performance improvements, but that got
> b0rked at some point ;(
>
> regards
> - Timo
>
Well, whatever it is, this means that the web application fills all the
memory and crashes every 30-40 requests.
Luckily there are not many people who read the site :)
Gabor
