On 05 Apr 2014, at 23:35, Joachim Geidel <joachim.gei...@onlinehome.de> wrote:
> Hi Igor, > > thanks a lot, your analysis is correct, and it helped. > > Am 05.04.2014 um 17:05 schrieb Igor Stasenko: >> so, without going deep into implementation details, just by reading comment >> i can already see potential bottleneck - using #become: operation which is >> veery slow. > > Yes, #become: is *very* slow in Pharo. No problem at all in VisualWorks or > Dolphin Smalltalk or Pharo 1.2, though! > > Time millisecondsToRun: [1000 timesRepeat: [String new become: String new ]] > > Pharo 3.0 (and also in 2.0 and 1.4): > 3948 3495 2891 2532 3162 > > Pharo 1.2 with the Squeak 4.2.5beta1U VM: > 90 89 82 90 72 these numbers are strange. Because mariano used a lot become: and he did not report a factor like that. Thanks for reporting them. > > VisualWorks 7.9.1: note that this is measured in microseconds: > Time microsecondsToRun: [1000 timesRepeat: [String new become: String new ]] > 211 208 222 212 208 this will be fixed with spur and body. > > That’s a factor of more than 10.000! IMHO, someone should have a look at the > primitives involved. > >> also, by tracking senders of #knownJavaSubclasses , i see there's also uses >> of #become operation.. >> >> So, my first verdict is: >> - excessive use of #become ==> slow performance >> :) >> >> (sure, i have no idea if you can avoid using become or not, but my bet this >> is main reason of low performance) > > Well, given the measurements above, I wouldn’t say that the reason is > excessive use of #become:, but the extremely slow implementation of #become: > in Pharo since 1.4. However, I managed to remove the need for sending > #become: in #findClassFor:, but not in the second place. This reduces the > time to start a Java VM to 5-6 seconds on my aged machine (2.4 GHz Intel Core > 2 Duo from early 2008). The benchmark which I mentioned in my announcement > and which took 12 seconds came down to less than 0.2 seconds. That's a little > more than the 0.11 seconds in VisualWorks, but at least in the same order of > magnitude. > > Thanks again! > Joachim > >
