hi Eric, Thanks for the reply. clear cache was triggered by the test case on every page load and we expected it to be light weight as there is hardly any js, but it turned out to be costly.
furthur looking in to it suggests that v8 maintains all the bultin and dom objects in the heap, where are jsc maintains it outside the heap, so even without a clear cache, the heap grows quickly (~300-400k on each page) on continuous page loads triggering many costly gcs in v8. thanks, Zaheer On Fri, Jul 2, 2010 at 1:19 PM, Erik Corry <[email protected]> wrote: > Calling a GC on clear cache is a heuristic, to try to find a good time to do > a large GC. The thinking behind it was that clear cache would be called > when memory was almost exhausted, and that it would be a good idea for V8 to > reduce its memory usage at that point. It was expected that the clear cache > event would be very rare. > Is 'clear cache' happening a lot? > In general a GCed system will often slow down dramatically just before > running out of memory. Also, running out of memory is not a recoverable > event. So it's best if you can avoid running out of memory. :-) > Den 18. jun. 2010 11.25 skrev zaheer ahmad <[email protected]>: >> >> hi, >> iam running some page cycler tests on android (with v8 - June 4 >> Bleeding Edge) that invoke LowMemoryCondition on every cycle (through >> ClearCache). I have very limited js in my tests <0.5% evaluation time, >> even then every request seems to be taking ~200-300ms. Is this a known >> issue? if not i can hopefully simulate a test case. >> >> In addition, the trigger ClearCache which is primarily a disk clear >> request may not be triggering a Low memory request IMO. >> Interestingly the JSC version in this case is quite fast (though it >> also seems be doing a compact). i havent checked the internals though. >> >> #if USE(JSC) >> // force JavaScript to GC when clear cache >> WebCore::gcController().garbageCollectSoon(); >> #elif USE(V8) >> WebCore::Frame* pFrame = GET_NATIVE_FRAME(env, obj); >> pFrame->script()->lowMemoryNotification(); >> #endif // USE(JSC) >> >> Thanks in advance for any inputs. >> >> Regards, >> Zaheer >> >> -- >> v8-users mailing list >> [email protected] >> http://groups.google.com/group/v8-users > > > > -- > Erik Corry, Software Engineer > Google Denmark ApS. CVR nr. 28 86 69 84 > c/o Philip & Partners, 7 Vognmagergade, P.O. Box 2227, DK-1018 Copenhagen K, > Denmark. > > -- > v8-users mailing list > [email protected] > http://groups.google.com/group/v8-users -- v8-users mailing list [email protected] http://groups.google.com/group/v8-users
