I'd rather not have the format of the log changed, but simplifying the arguments would be great. Isn't that the only change being proposed?<br><br>Doesn't everyone have a Perl script that they use to pull out the stuff from the log that's relevant and put it in gnuplot or Excel or something?<br>
<br>Jim<br><br><br><br><div class="gmail_quote">On Fri, Apr 4, 2008 at 3:46 AM, Michael Finocchiaro <<a href="mailto:michael.finocchiaro@gmail.com">michael.finocchiaro@gmail.com</a>> wrote:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
That is good idea to make PGCTS the default with PGCD and I also agree that the TraceClassUnloading is annoying in a gc log.<br><br>I would propose that you look at HP's JVM GC log format as something far easier to parse than the current format.<br>
<br><a href="http://docs.hp.com/en/5992-1918/ch01s25.html" target="_blank">http://docs.hp.com/en/5992-1918/ch01s25.html</a><br><br>or perhaps the jstatd format. <br><br>After about 5 or 6 years I can almost eyeball the current file format but a numeric based, space or comma-separated list of the GC cause and the memory space allocations would be a lot easier for post-mortem diagnosis and tuning. And, at least in the HP case, the overhead is very minimal (you get almost the same amount of detail as from -XX:+PrintTenuringDistribution in a single line)...and since there still is not a robust and easy-to-use equivalent of HPjmeter (disclosure - I worked for 10 years for HP) for analyzing the JavaSoft HotSpot JVMs, this would be an improvement.<br>
<br>My 2 cents,<br>Fino<div><div></div><div class="Wj3C7c"><br><br><div class="gmail_quote">On Thu, Apr 3, 2008 at 11:22 PM, Tony Printezis <<a href="mailto:tony.printezis@sun.com" target="_blank">tony.printezis@sun.com</a>> wrote:<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
We're proposing a few small changes (and on significant one) to the way<br>
the GC logging flags work:<br>
<br>
a) When +PrintGCDetails is set, +PrintGCTimeStamps should be set by<br>
default (currently, it has to be set explicitly; what we've found is<br>
that it's always more useful to have the time stamps in a GC log when<br>
analyzing it)<br>
b) When -XXloggc: is set, +PrintGCDetails and +PrintGCTimeStamps are set<br>
automatically (instead of -verbosegc and +PrintGCTimeStamps) (again, for<br>
us, it's always more useful to have the more detailed +PrintGCDetails<br>
output in the log when analyzing it)<br>
c) When -verbosegc, +PrintGCDetails, or -Xloggc: are set,<br>
+TraceClassUnloading is _not_ automatically set, as it is now (it<br>
polutes the output a bit during Full GCs)<br>
<br>
Notice that, for the above, you'll still be able to get the old behavior<br>
by setting / unsetting some flags; we're just trying to set more<br>
sensible defaults.<br>
<br>
The more significant proposal:<br>
<br>
d) Eliminate the -verbosegc format in favor of the (more detailed and<br>
more useful, though less concise) +PrintGCDetails format. Do people<br>
still heavily use and rely on the -verbosegc format in a way that<br>
migration to the +PrintGCDetails format will be difficult?<br>
<br>
Your thoughts and feedback on the above will be appreciated. Thank you,<br>
<br>
Tony, HS GC Group<br>
<br>
--<br>
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</blockquote></div><br><br clear="all"><br></div></div><font color="#888888">-- <br>Michael Finocchiaro<br><a href="mailto:michael.finocchiaro@gmail.com" target="_blank">michael.finocchiaro@gmail.com</a><br>Mobile Telephone: +33 6 67 90 64 39<br>
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