Maybe in the last case you also need to send nextPut: instead of
nextPutAll:...
On 4/27/11 23:35 , jannik.laval wrote:
Hi all,
I am playing with MessageTally, and I have a strange result with
prealocation.
Here is my example. I am working on a PharoCore1.3, with a VM4.2.5
First of all, I spy this source code:
====
MessageTally spyOn:
[ 500 timesRepeat: [
| str |
*str := ''*.
9000 timesRepeat: [ str := str, 'A' ]]].
====
The result appears after *24 961 ms*.
An optimization is to use a Stream. Here is my source code:
===
MessageTally spyOn:
[ 500 timesRepeat: [
| str |
*str := WriteStream on: (String new)*.
9000 timesRepeat: [ str nextPut: $A ]]].
===
The result appears after *812 ms*, which is a large improvement.
Now, we could optimize again using the preallocation. Here is my source
code:
====
MessageTally spyOn:
[ 500 timesRepeat: [
| str |
*str := WriteStream on: (String new: 10000)*.
9000 timesRepeat: [ str nextPutAll: 'A' ]]].
====
And the result is strange: it makes 2 times slower to display the result.
The result appears after 1656 ms.
Here is the spy result:
===
- 1656 tallies, 1656 msec.
**Tree**
--------------------------------
Process: (40s) 464519168: nil
--------------------------------
**Leaves**
*22.9% {380ms} UndefinedObject>>DoIt*
22.5% {373ms} SmallInteger(Integer)>>timesRepeat:
22.2% {368ms} WriteStream>>nextPutAll:
===
There is the call of UndefinedObject>>DoIt which is added and takes time.
Does anyone know what is done during the preallocation ?
Why is it slower than non-preallocation ?
Thanks for your answers.
Jannik
