So the FloatingPoint -> Float64 is probably a good idea, but isn't the 
bottleneck.

I profiled the random access section:
t[1]
@profile for i in 1:n
  t[rand(1:n)]
end
Profile.print()

and all the work is going on in lines 84,87, and 88, as you'd expect.
What I can't figure out is why it is allocating any memory...

On Sunday, May 11, 2014 7:59:42 PM UTC-4, Yuri Vishnevsky wrote:
>
> Oddly, that makes it *slower*...
>
> julia> benchmark(1000000)
> Timing 1000000 insert operations.
> elapsed time: 11.637004929 seconds (1324768744 bytes allocated)
> Timing 1000000 random access operations.
> elapsed time: 15.640938079 seconds (1047763544 bytes allocated)
> Timing 1000000 remove operations.
> elapsed time: 9.440363056 seconds (1138842368 bytes allocated)
>
> (vs. 7s, 16s, and 5s with FloatingPoint priorities,  respectively.)
>
> – Yuri
>
> On Sunday, May 11, 2014 7:39:17 PM UTC-4, John Myles White wrote:
>>
>> Try changing FloatingPoint to Float64 and you may seem a substantial 
>> performance boost. 
>>
>>  — John 
>>
>> On May 11, 2014, at 4:32 PM, Yuri Vishnevsky <[email protected]> wrote: 
>>
>> > I'm working on a Julia implementation of a Treap, a data structure that 
>> maintains a sorted collection of elements and allows insertion, deletion, 
>> and random access in O(log n) time (http://en.wikipedia.org/wiki/Treap). 
>> > 
>> > So far I've implemented the basic functions, but performance is far 
>> slower than I'd like and I am having trouble understanding why. 
>> > 
>> > Here's the gist: https://gist.github.com/yurivish/aff46c190c1ac538c46f 
>> > 
>> > I've written a small benchmark script to try and diagnose the problem. 
>> It reports lots of memory use for larger collections, even during calls to 
>> getindex(). Here's the output for several runs; the function, which is 
>> included in the gist, creates and queries a list of Int64s. 
>> > 
>> > julia> benchmark(100) 
>> > Timing 100 insert operations. 
>> > elapsed time: 0.000188415 seconds (11200 bytes allocated) 
>> > Timing 100 random access operations. 
>> > elapsed time: 0.000294615 seconds (0 bytes allocated) 
>> > Timing 100 remove operations. 
>> > elapsed time: 6.6692e-5 seconds (0 bytes allocated) 
>> > 
>> > julia> benchmark(1000) 
>> > Timing 1000 insert operations. 
>> > elapsed time: 0.0024881 seconds (208080 bytes allocated) 
>> > Timing 1000 random access operations. 
>> > elapsed time: 0.003553674 seconds (95776 bytes allocated) 
>> > Timing 1000 remove operations. 
>> > elapsed time: 0.001143906 seconds (74496 bytes allocated) 
>> > 
>> > julia> benchmark(1000000) 
>> > Timing 1000000 insert operations. 
>> > elapsed time: 6.920983574 seconds (521837776 bytes allocated) 
>> > Timing 1000000 random access operations. 
>> > elapsed time: 16.232631535 seconds (1010908560 bytes allocated) 
>> > Timing 1000000 remove operations. 
>> > elapsed time: 5.399104537 seconds (387715296 bytes allocated) 
>> > 
>> > Any insight into potential improvements to (or problems with) the code 
>> would be appreciated. 
>> > 
>> > Cheers, 
>> > Yuri 
>>
>>

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