David,
I've made a stupid mistake and please ignore it...
Regards,
Yunda
> -----Original Message-----
> From: 云达(Yunda)
> Sent: Tuesday, May 07, 2013 5:44 PM
> To: 'David Holmes'
> Cc: hotspot-runtime-...@openjdk.java.net;
> serviceability-dev@openjdk.java.net
> Subject: RE: [PATCH] EnableTracing: output from multiple threads may be mixed
> together
>
> Hi David,
>
> Thanks for the review and I see your concern. Please see the updated change
> below:
>
> diff -r 627cf9e9ea31 src/share/vm/runtime/globals.hpp
> --- a/src/share/vm/runtime/globals.hpp Mon May 06 10:29:49 2013 -0700
> +++ b/src/share/vm/runtime/globals.hpp Tue May 07 17:38:58 2013 +0800
> @@ -3634,7 +3634,10 @@
> "Include GC cause in GC logging")
> \
>
> \
> product(bool, EnableTracing, false,
> \
> - "Enable event-based tracing")
> + "Enable event-based tracing")
> \
> +
> \
> + product(bool, UseLockedTracing, false,
> \
> + "Use locked-tracing when doing event-based tracing")
>
> /*
> * Macros for factoring of globals
> diff -r 627cf9e9ea31 src/share/vm/trace/traceEventClasses.xsl
> --- a/src/share/vm/trace/traceEventClasses.xsl Mon May 06 10:29:49 2013
> -0700
> +++ b/src/share/vm/trace/traceEventClasses.xsl Tue May 07 17:38:58 2013
> +0800
> @@ -132,6 +132,9 @@
> void writeEvent(void) {
> ResourceMark rm;
> HandleMark hm;
> + if (UseLockedTracing) {
> + ttyLocker ttyl;
> + }
> TraceStream ts(*tty);
> ts.print("<xsl:value-of select="@label"/>: ["); <xsl:apply-templates
> select="value|structvalue" mode="write-data"/>
>
> Regards,
> Yunda
>
> > -----Original Message-----
> > From: David Holmes [mailto:david.hol...@oracle.com]
> > Sent: Tuesday, May 07, 2013 10:39 AM
> > To: 云达(Yunda)
> > Cc: hotspot-runtime-...@openjdk.java.net;
> > serviceability-dev@openjdk.java.net
> > Subject: Re: [PATCH] EnableTracing: output from multiple threads may
> > be mixed together
> >
> > Hi Yunda,
> >
> > There is a potential problem with using a ttyLocker here, depending on
> > exactly what events are being traced and from where - you must always
> > be in code where it is both safe to acquire the lock, and safe to
> > block waiting for the lock if it is not available.
> >
> > I think I would prefer to see unlocked tracing by default with a flag
> > to use locked-tracing if requested.
> >
> > David
> >
> > On 19/04/2013 6:26 PM, 云达(Yunda) wrote:
> > > Hi all,
> > >
> > > I found that the output from multiple threads may be mixed together
> > > when using EnableTracing. It happens many times in my test case like this:
> > >
> > > Allocation outside TLAB: [Allocation in new TLAB: [Allocation in new
> > > TLAB: [Allocation in new TLAB: [Class = [C, Allocation in new TLAB:
> > > [Class = [I, Allocation in new TLAB: [Java Monitor Wait: [Class =
> > > java/lang/String, Allocation Size = 24, Allocation Size = 24, Class
> > > = java/lang/String, Class = [I, Allocation in new TLAB: [Class = [C,
> > > Allocation in new TLAB: [Allocation Size = 192]
> > >
> > > Class =
> > > com/sun/org/apache/xerces/internal/dom/DeferredElementNSImpl,
> > > Allocation Size = 24, Allocation Size = 24, TLAB Size = 23712280]
> > >
> > > TLAB Size = 24607080]
> > >
> > > Allocation Size = 24, Monitor Class = java/lang/ref/Reference$Lock,
> > > TLAB Size = 25054480]
> > >
> > > TLAB Size = 25054480]
> > >
> > > Allocation in new TLAB: [Class = [CTLAB Size = 24607080]
> > >
> > > Allocation Size = 72, Class = [C, TLAB Size = 24159728]
> > >
> > > , Allocation Size = 32, TLAB Size = 23712288]
> > >
> > > It's very confusing and it's even not easy to tell how many events
> > > there are. I think the reason is that the writeEvent() method of
> > > each
> > > Event* class output the fields of event one by one without using any
> > > lock. So I made a small patch which add ttyLocker to writeEvent()
> > > method and after applying this patch there's no output mixed
> > > together in my test case(against
> http://hg.openjdk.java.net/hsx/hsx24/hotspot/):
> > >
> > > diff -r edd1619a3ae4 src/share/vm/trace/traceEventClasses.xsl
> > >
> > > --- a/src/share/vm/trace/traceEventClasses.xsl Thu Apr 18 13:50:58
> > > 2013 -0700
> > >
> > > +++ b/src/share/vm/trace/traceEventClasses.xsl Fri Apr 19 16:12:38
> > > +++ 2013
> > > +0800
> > >
> > > @@ -132,6 +132,7 @@
> > >
> > > void writeEvent(void) {
> > >
> > > ResourceMark rm;
> > >
> > > HandleMark hm;
> > >
> > > + ttyLocker ttyl;
> > >
> > > TraceStream ts(*tty);
> > >
> > > ts.print("<xsl:value-of select="@label"/>: [");
> > >
> > > <xsl:apply-templates select="value|structvalue" mode="write-data"/>
> > >
> > > I searched before sending this mail I didn't find anyone who
> > > covering thisJ
> > >
> > > Regards,
> > >
> > > Yunda
> > >
> > >
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________________________________
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