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Hi again, :-)<br>
<br>
Here is an updated webrev where PrintGCCause is off by default in
JDK7 but on by default in JDK8:<br>
<a class="moz-txt-link-freetext" href="http://cr.openjdk.java.net/~brutisso/7166894/webrev.05/">http://cr.openjdk.java.net/~brutisso/7166894/webrev.05/</a><br>
<br>
The relevant change is in arguments.cpp:<br>
<a class="moz-txt-link-freetext" href="http://cr.openjdk.java.net/~brutisso/7166894/webrev.05/src/share/vm/runtime/arguments.cpp.udiff.html">http://cr.openjdk.java.net/~brutisso/7166894/webrev.05/src/share/vm/runtime/arguments.cpp.udiff.html</a><br>
<br>
With this proposal there is still one slight change in JDK7 logging.
For full GCs that were triggered by System.gc() calls we used to log
the cause. Now this will not happen unless you add
-XX:+PrintGCCause. This will not break any parsers, but it might
make some parsers miss System.gc() calls.<br>
<br>
I think we are getting closer to wrapping this change up. It is a
little unclear to me who would like to be listed as reviewers. Could
those that would like to be reviewers please take a look at the
latest webrev and let me know.<br>
<br>
Thanks,<br>
Bengt <br>
<br>
<br>
On 2012-05-11 19:51, Srinivas Ramakrishna wrote:
<blockquote
cite="mid:CABzyjyk7xwBUSWcEuh8FmqwJ_zRKcm6CnrwY7Af0DbzqizZAMg@mail.gmail.com"
type="cite">Mikael, thanks for sounding that note of caution...
what you say makes sense.<br>
<br>
-- ramki<br>
<br>
<div class="gmail_quote">On Fri, May 11, 2012 at 10:17 AM, Mikael
Vidstedt <span dir="ltr"><<a moz-do-not-send="true"
href="mailto:mikael.vidstedt@oracle.com" target="_blank">mikael.vidstedt@oracle.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt
0.8ex; border-left: 1px solid rgb(204, 204, 204);
padding-left: 1ex;">
<div bgcolor="#FFFFFF" text="#000000"> <br>
I'm all for improving the information in the log messages,
great work! However, I'm not sure I'm warm and fuzzy about
potentially breaking users' log parsers in a minor update.
My preference would be to have the PrintGCCause flag be
default false in jdk7 and default true in jdk8+. In general
I'd prefer to only change the log messages in major
releases.<br>
<br>
Reasonable?<br>
<br>
Cheers,<br>
Mikael
<div>
<div class="h5"><br>
<br>
On 2012-05-11 07:30, Bengt Rutisson wrote:
<blockquote type="cite"> <br>
Hi Kris,<br>
<br>
Thanks again for looking at this.<br>
<br>
I had to make some minor changes make it compile on
all platforms. Mostly some explicit casts to const
char*. Here is an updated webrev:<br>
<a moz-do-not-send="true"
href="http://cr.openjdk.java.net/%7Ebrutisso/7166894/webrev.04/"
target="_blank">http://cr.openjdk.java.net/~brutisso/7166894/webrev.04/</a><br>
<br>
More comments inline.<br>
<br>
On 2012-05-08 16:43, Krystal Mok wrote:
<blockquote type="cite">Hi Bengt,
<div><br>
</div>
<div>The current factoring looks nice and uniform.
Thanks :-)</div>
<div><br>
</div>
<div>But for most minor GCs and both CMS pause
phases, the extra logging doesn't really give
additional information.</div>
<div>Most minor GCs are going to say "Allocation
Failure", and the two CMS phases would change
from, e.g.</div>
<div><br>
</div>
<div>[GC [1 CMS-initial-mark</div>
<div><br>
</div>
<div>to something like</div>
<div><br>
</div>
<div>[GC (CMS Initial Mark) [1 CMS-initial-mark</div>
<div><br>
</div>
<div>which is probably reasonable given the scope of
the change, but not really helpful.</div>
<div>The "real cause", such as which generation (or
perhaps System.gc() with
ExplicitGCInvokesConcurrent, or even GC locker) is
triggering this collection cycle, may be more
useful, but it's hard to fit into the current
form.</div>
</blockquote>
<br>
Yes, I think you are correct in both cases. The gc
cause that we have available does not always add a lot
of information. This is relevant to fix but it is a
slightly different issue than what this patch sets out
to fix. Let's try to get this in first and then
evaluate how the GC causes should be set.<br>
<br>
Thanks,<br>
Bengt<br>
<br>
<blockquote type="cite">
<div><br>
</div>
<div>- Kris<br>
<br>
<div class="gmail_quote">On Tue, May 8, 2012 at
10:18 PM, Bengt Rutisson <span dir="ltr"><<a
moz-do-not-send="true"
href="mailto:bengt.rutisson@oracle.com"
target="_blank">bengt.rutisson@oracle.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:
0pt 0pt 0pt 0.8ex; border-left: 1px solid
rgb(204, 204, 204); padding-left: 1ex;">
<div bgcolor="#FFFFFF" text="#000000"> <br>
Hi again everyone,<br>
<br>
It seems like the feedback on hotspot-gc-use
is that we should add the GC cause to all
collectors but also provide a switch to turn
this logging off.<br>
<br>
Here is an updated webrev:<br>
<a moz-do-not-send="true"
href="http://cr.openjdk.java.net/%7Ebrutisso/7166894/webrev.03/"
target="_blank">http://cr.openjdk.java.net/~brutisso/7166894/webrev.03/</a><br>
<br>
Changes:<br>
* GC cause logged for all collectors<br>
* Added the flag -XX:-PrintGCCause to turn
the new information off<br>
* Refactored the string concatenation code
into a helper class<br>
<br>
I guess I will also have to update the CR to
now reflect the fact that this does not just
concern full GCs anymore.<br>
<br>
Thanks,<br>
Bengt
<div>
<div><br>
</div>
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