Rana, so, you do not have any benchmark that "feels" the change? Maybe you could publish a relevant microbenchmark? Otherwize I cannot say this complex change is a "stability fix". It potentially creates more instability, and performance impact is not measured, right?
On the 0x35C day of Apache Harmony Rana Dasgupta wrote: > Egor, > > On 25 Sep 2007 10:54:59 +0400, Egor Pasko <[EMAIL PROTECTED]> wrote: > > Rana, > > > > what do you mean ny saying 1) too expensive 2) shows me no variation > > in performance? So, is it expensive or not? > > I think that the reason that witching on CU does not show any impact > on performance of SpecJBB( 32) is that it does not cause any > significant number of full collections and has no classes to unload. > As such, it is not a great test case for class unloading. A good test > scenario would be one that did both. There will be some tradeoff of > performance loss against memory footprint reduction of this feature > that only good scenarios will help tune. > > > > > how about DaCapo? would this change be within a noise level for > > DaCapo? > > > > Let's ask performance people, most likely, they know :) > > > > Taking only SpecJBB into accout is not enough to consider the > > change that potentially affects performance to a big extent. > > > > > BTW, I have been unable to find a scenario that stresses the gc > > > heap, and needs to unload unused classes, and it would be good find > > > such test cases. > > > > BTW, why dont't we start measuring memory footprint of the JVM? The > > strategy of our performance testing is AFAIR: > > 1) add infinite number of memory > > 2) measure ticks > > > > but none of us would notice if the stuff grows to a memory eating pig, > > so real user experience would be constant swapping. > > Yes, I agree with this. Overall, Pavel's comment to turn on CU as a > memory leak oriented stability feature post M3 sounds sensible. I'll > do this, we can commit the change after M3. > > > > > BTW2: does anybody update [1] regularly? if so, dear updater, do you > > think, it is reasonable to add the column "memory footprint"? > > > > [1] http://harmony.apache.org/performance.html > > > > -- > > Egor Pasko > > > > > -- Egor Pasko
