Good catch. With criterium, I can detect the small performance improvement.
volatile: Evaluation count : 7550019420 in 60 samples of 125833657 calls.
Execution time mean : 6.345042 ns
Execution time std-deviation : 0.126086 ns
Execution time lower quantile : 6.223058 ns ( 2.5%)
Execution time upper quantile : 6.525868 ns (97.5%)
Overhead used : 1.651549 ns
AtomicLong: Evaluation count : 6925392540 in 60 samples of 115423209 calls.
Execution time mean : 7.156855 ns
Execution time std-deviation : 0.136142 ns
Execution time lower quantile : 7.010743 ns ( 2.5%)
Execution time upper quantile : 7.362120 ns (97.5%)
Overhead used : 1.651549 ns
AtomicReference: Evaluation count : 6014401080 in 60 samples of 100240018
calls.
Execution time mean : 8.342217 ns
Execution time std-deviation : 0.126856 ns
Execution time lower quantile : 8.129171 ns ( 2.5%)
Execution time upper quantile : 8.511877 ns (97.5%)
Overhead used : 1.651549 ns
On Wednesday, March 11, 2015 at 1:50:37 PM UTC-4, tbc++ wrote:
>
> Actaully I think it comes down to the use of the rather generic Deref. I
> fired up a repl and ran the following
>
> (let [v (clojure.lang.Volatile. {})]
> (dotimes [x ...]
> (.reset v (.deref v))))
>
> I'm seeing very similar times to the one for the AtomicReference.
>
> Timothy
>
> On Wed, Mar 11, 2015 at 11:08 AM, Brent Millare <brent....@gmail.com
> <javascript:>> wrote:
>
>> I find it hard to believe GC would be a factor since there is very little
>> being generated here. Also, while the outside loop is only 10 iterations of
>> timings, in the inside loops the code is called for 100 million iterations.
>> Anyways, running it with criterium didn't change the ranking.
>>
>> Here is the output:
>> volatile: WARNING: Final GC required 1.149417308725186 % of runtime
>> Evaluation count : 4156079100 in 60 samples of 69267985 calls.
>> Execution time mean : 12.975339 ns
>> Execution time std-deviation : 0.188921 ns
>> Execution time lower quantile : 12.823222 ns ( 2.5%)
>> Execution time upper quantile : 13.272950 ns (97.5%)
>> Overhead used : 1.613416 ns
>> AtomicLong: Evaluation count : 6921767160 in 60 samples of 115362786
>> calls.
>> Execution time mean : 7.155989 ns
>> Execution time std-deviation : 0.124147 ns
>> Execution time lower quantile : 7.048738 ns ( 2.5%)
>> Execution time upper quantile : 7.330448 ns (97.5%)
>> Overhead used : 1.613416 ns
>> AtomicReference: Evaluation count : 5814704460 in 60 samples of 96911741
>> calls.
>> Execution time mean : 8.791224 ns
>> Execution time std-deviation : 0.185229 ns
>> Execution time lower quantile : 8.564921 ns ( 2.5%)
>> Execution time upper quantile : 9.340265 ns (97.5%)
>> Overhead used : 1.613416 ns
>>
>> Found 4 outliers in 60 samples (6.6667 %)
>> low-severe 2 (3.3333 %)
>> low-mild 2 (3.3333 %)
>> Variance from outliers : 9.4134 % Variance is slightly inflated by
>> outliers
>> atom: Evaluation count : 4038207840 in 60 samples of 67303464 calls.
>> Execution time mean : 13.007604 ns
>> Execution time std-deviation : 0.202285 ns
>> Execution time lower quantile : 12.819268 ns ( 2.5%)
>> Execution time upper quantile : 13.275983 ns (97.5%)
>> Overhead used : 1.613416 ns
>>
>> Note: I bench the get/set expression, not the creation of the
>> volatile/atomic*/atom
>>
>> eg.
>> (let [v (volatile! 1)]
>> (c/bench (vreset! v @v)))
>>
>> On Wednesday, March 11, 2015 at 12:30:06 PM UTC-4, tbc++ wrote:
>>>
>>> There's many other factors involved here though, GC, JIT warmup, etc.
>>> That's kindof what criterium helps out with, removing all the variables and
>>> running something until the JIT has warmed up enough (10 iterations
>>> probably isn't enough).
>>>
>>> Timothy
>>>
>>>
>>> --
>> You received this message because you are subscribed to the Google
>> Groups "Clojure" group.
>> To post to this group, send email to clo...@googlegroups.com
>> <javascript:>
>> Note that posts from new members are moderated - please be patient with
>> your first post.
>> To unsubscribe from this group, send email to
>> clojure+u...@googlegroups.com <javascript:>
>> For more options, visit this group at
>> http://groups.google.com/group/clojure?hl=en
>> ---
>> You received this message because you are subscribed to the Google Groups
>> "Clojure" group.
>> To unsubscribe from this group and stop receiving emails from it, send an
>> email to clojure+u...@googlegroups.com <javascript:>.
>> For more options, visit https://groups.google.com/d/optout.
>>
>
>
>
> --
> “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)
>
--
You received this message because you are subscribed to the Google
Groups "Clojure" group.
To post to this group, send email to clojure@googlegroups.com
Note that posts from new members are moderated - please be patient with your
first post.
To unsubscribe from this group, send email to
clojure+unsubscr...@googlegroups.com
For more options, visit this group at
http://groups.google.com/group/clojure?hl=en
---
You received this message because you are subscribed to the Google Groups
"Clojure" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to clojure+unsubscr...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.
