<p>Thanks for the explanation Bengt - all good from me, FWIW :).</p>
<p>Sent from my phone</p>
<div class="gmail_quote">On Jun 25, 2012 9:24 AM, "Bengt Rutisson" <<a href="mailto:bengt.rutisson@oracle.com">bengt.rutisson@oracle.com</a>> wrote:<br type="attribution"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div bgcolor="#FFFFFF" text="#000000">
<div><br>
Hi Vitaly,<br>
<br>
On 2012-06-21 14:36, Vitaly Davidovich wrote:<br>
</div>
<blockquote type="cite">Hi Bengt,
<div><br>
</div>
<div>Looks good. One question: the asserts you added check
against _active_gc_threads, but the arrays are sized with
parallel_gc_threads. The assumption then is that
active_gc_threads <= parallel_gc_threads? If so, maybe assert
that piece as well. </div>
</blockquote>
<br>
I see your point. Currently _active_gc_threads is set up to be the
same as parallel_gc_threads, but I can add an assert to that effect
in the constructor of
G1GCPhaseTimes.<br>
<br>
<blockquote type="cite">
<div>Also, maybe consider moving the range asserts into a macro or
helper function so that you don't have to repeat the exact same
2 lines?</div>
</blockquote>
<br>
Somehow I find the inlined asserts more readable. I'll think about
it. Thanks for the suggestion.<br>
<br>
<blockquote type="cite">
<div><br>
</div>
<div>Finally (forgot to mention this in my initial email), a minor
point -- should the sentinel -1234.0 value that you set the
arrays to be defined as a constant so if you, for some reason,
decide to change it, you just update 1 place? Very minor though
:).</div>
</blockquote>
<br>
Yes, this should be fixed. However, I just moved this code from one
place to anther and I plan on revisiting this code and cleaning it
up a bit with my next change. That change should remove the serial
special case in this code. Is it ok if I leave this cleanup for that
change?<br>
<br>
<blockquote type="cite">
<div><br>
</div>
<div>As for worker_i being unsigned, I was thinking the method
would take unsigned which perhaps better expresses the
range/intent of the value, but can cast internally to signed to
do array lookup. Anyhow, not a big deal and what you have is
fine, obviously.</div>
</blockquote>
<br>
Yes, I tend to agree, but I think I'll leave them as int for now.
Maybe I'll change this too as part of my next cleanup.<br>
<br>
<blockquote type="cite">
<div>The output looks nice with your changes -- I wonder though if
even whitespace changes are deemed too risky in terms of
possibly breaking client parsers (would have to be fairly
brittle ones, but nonetheless).</div>
</blockquote>
<br>
Right. However, it looks to me like this output has been changing
its indentation levels over time, so if any parsers break due to
white space changes they are probably already broken ;-)<br>
<br>
Thanks again for looking at this!<br>
Bengt<br>
<br>
<blockquote type="cite">
<div><br>
</div>
<div>Thanks,</div>
<div><br>
</div>
<div>Vitaly<br>
<br>
<div class="gmail_quote">On Thu, Jun 21, 2012 at 7:54 AM, Bengt
Rutisson <span dir="ltr"><<a href="mailto:bengt.rutisson@oracle.com" target="_blank">bengt.rutisson@oracle.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><br>
Hi again,<br>
<br>
Updated webrev:<br>
<a href="http://cr.openjdk.java.net/%7Ebrutisso/7178361/webrev.01/" target="_blank">http://cr.openjdk.java.net/~brutisso/7178361/webrev.01/</a><br>
<br>
I added some asserts as suggested by Vitaly and I did some
white space changes to the TraceGen0Time logging. I hope
this will not break any parsers. It is just intended to
align the output up a bit better to be more readable.<br>
<br>
Here is a webrev with just the change I made compared to my
previous webrev:<br>
<a href="http://cr.openjdk.java.net/%7Ebrutisso/7178361/webrev.00-01-diff/" target="_blank">http://cr.openjdk.java.net/~brutisso/7178361/webrev.00-01-diff/</a><br>
<br>
Here is an example of what the TraceGen0Time output looks
like after my change:<br>
<br>
ALL PAUSES<br>
Total = 0.95 s (avg = 63.44 ms)<br>
(num = 15, std
dev = 47.84 ms, max = 150.30 ms)<br>
<br>
<br>
Young GC Pauses: 14<br>
Mixed GC Pauses: 1<br>
<br>
EVACUATION PAUSES<br>
Evacuation Pauses = 0.95 s (avg = 63.44 ms)<br>
(num = 15, std
dev = 47.84 ms, max = 150.30 ms)<br>
Root Region Scan Wait = 0.00 s (avg = 0.00 ms)<br>
Parallel Time = 0.94 s (avg = 62.39 ms)<br>
Ext Root Scanning = 0.11 s (avg = 7.22 ms)<br>
SATB Filtering = 0.00 s (avg = 0.00 ms)<br>
Update RS = 0.04 s (avg = 2.81 ms)<br>
Scan RS = 0.03 s (avg = 2.07 ms)<br>
Object Copy = 0.75 s (avg = 49.75 ms)<br>
Termination = 0.00 s (avg = 0.02 ms)<br>
Parallel Other = 0.01 s (avg = 0.51 ms)<br>
Clear CT = 0.00 s (avg = 0.09 ms)<br>
Other = 0.01 s (avg = 0.90 ms)<br>
<br>
MISC<br>
Stop World = 0.01 s (avg = 0.48 ms)<br>
(num = 15, std
dev = 0.19 ms, max = 0.79 ms)<br>
Yields = 0.00 s (avg = 0.27 ms)<br>
(num = 2, std
dev = 0.05 ms, max = 0.32 ms)<br>
<br>
Thanks,<br>
Bengt
<div>
<div><br>
<br>
<br>
On 2012-06-20 15:15, Bengt Rutisson wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<br>
Hi everyone,<br>
<br>
Could I please have some reviews for this change:<br>
<a href="http://cr.openjdk.java.net/%7Ebrutisso/7178361/webrev.00/" target="_blank">http://cr.openjdk.java.net/~brutisso/7178361/webrev.00/</a><br>
<br>
Background<br>
As part of the PrintGC and PrintGCDetails logging
there is information about how long the GC pause was.
The timing of the pause was done differently in G1
depending on whether PrintGC or PrintGCDetails were
enabled. It turns out that PrintGCDetails was just
timing part of the pause.<br>
<br>
This change will make both PrintGC and PrintGCDetails
use the same timing. To achieve this I had to refactor
the code a bit. I moved all the timing data out of
G1CollectorPolicy into a new class called
G1GCPhaseTimes.<br>
<br>
My intention is that this change should not alter the
format of the output of PrintGC or PrintGCDetails. It
should just correct the timing data.<br>
<br>
However, I did find that we are collecting timing
information about card counts, under an #ifdef. I
moved this to the finest log level instead. This does
not change the existing format for normal usage of
PrintGC or PrintGCDetails.<br>
<br>
Also, I had to update how the TraceGen0Time data is
logged. I will have another look at this, but my idea
was to leave the format exactly as it was. However, I
think the format has decayed over time so maybe I'll
try to clean it up.<br>
<br>
I intend to follow this change up with a change to
remove the special treatment of the single threaded
case for PrintGCDetails (tracked in CR 7178363).<br>
<br>
Finally, this work revealed an issue with how the
ergonomics in G1 measure the collection pauses. I did
not want to change this behavior now so I filed a
separate RFE for that (7178365: G1: Ergonomics only
count part of the collection pause).<br>
<br>
Bengt<br>
</blockquote>
<br>
</div>
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</blockquote>
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<br>
</div>
</blockquote>
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<br>
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