gc log analysis tools

[Neo Jia]

On 10/25/07, Ben Cheng <bccheng at google.com> wrote:
>
>
>
> On 10/25/07, Neo Jia <neojia at gmail.com> wrote:
> > Ben,
> >
> > Which one should be better? lower score or higher score? I assume it
> > should be higher based on what you said here.
>
>
> Oops, I forgot to clarify that. Yes, the higher the better.
>
> > And, what is the relation between score and time? Will the execution
> > time longer with a low score?
>
>
>
> The benchmark is doing fixed workload, so the score is simply calculated as
> work/s.
>
> > And how many minor GC and full GC in each of your execution? Just grep
> > and wc them.
>
>
>
> Almost all of them are minor GCs.

You may try the same ratio for these two configurations and check if
there is any difference.

Neo

>
> > For 32-bit and 64-bit machine, at least the default heap layout is
> > different. Are you trying to use same amount of nursery space and
> > mature space.
>
>
>
> I think I am just using the default ration. I only specify -Xmx and -Xms to
> the same amount without using -Xmn.
>
> > And for 64-bit machine, the Jitter is much more better than 32-bit
> > machine, a lot of optimization is added.
>
>
> I believe so, and that's why the 64-bit VM eventually provides 40% speedup
> with larger heap is given. I think under the same amount of heap space there
> are more GC activities in 64-bit VM due to larger object sizes. I will
> grep/wc the total gc time then.
>
> Thanks,
> -Ben
>
>
> > So ...
> >
> > Thanks,
> > Neo
> >
> > On 10/25/07, Ben Cheng <bccheng at google.com > wrote:
> > > The reason I am interested in this information is because I have a
> benchmark
> > > whose score is X using 32-bit VM and 2G of heap. When I switched to
> 64-bit
> > > build of the same VM, the score dropped to 0.77X with the same amount of
> > > heap. If I increase the heap size to 3.5G (on a machine with 4GB of
> RAM),
> > > the score went to to 1.40X.
> > >
> > > What I need is pretty basic - it sums up all the gc time from the
> verbose
> > > log during a benchmark run, as I want to verify if the change in gc time
> > > correlates to the change in performance. I can write a similar script to
> do
> > > that, but I just want to check to see if there is a working tool out
> there
> > > already. Apparently the verbose gc log format changed from 1.5 and
> beyond
> > > and the old script is not compatible.
> > >
> > > Thanks,
> > > -Ben
> > >
> > >
> > > On 10/25/07, Neo Jia < neojia at gmail.com> wrote:
> > > > Ben,
> > > >
> > > > What is your opion? I had one but not sure if it would work for you or
> not
> > > (
> > > >
> > > > I have not worked on JDK for a while ...
> > > >
> > > > Thanks,
> > > > Neo
> > > >
> > > > On 10/25/07, Ben Cheng < bccheng at google.com> wrote:
> > > > > Hi,
> > > > >
> > > > > I was trying to get a sense of total GC time spent in a Java app
> using
> > > 1.6
> > > > > JDK. The gc logs (w/ and wo/ parallel gc) seem to break the ancient
> tool
> > > > > gc_analyze.pl found on the web.
> > > > >
> > > > > Is there an update to date tool to produce the desired information
> for
> > > new
> > > > > JDKs?
> > > > >
> > > > > Thanks in advance,
> > > > > -Ben
> > > > >
> > > >
> > > >
> > > > --
> > > > I would remember that if researchers were not ambitious
> > > > probably today we haven't the technology we are using!
> > > >
> > >
> > >
> >
> >
> > --
> > I would remember that if researchers were not ambitious
> > probably today we haven't the technology we are using!
> >
>
>


-- 
I would remember that if researchers were not ambitious
probably today we haven't the technology we are using!