8188131: [PPC] Increase inlining thresholds to the same as other platforms

Tue Oct 24 07:24:43 UTC 2017

Hi Ogata, 

> It is helpful if you could explain what is the difference of the JIT
> behavior when the code cache is large enough and when it is the minimum
If the code cache is not large enough, code can get evicted and recompiled. 
Then the compiler threads keep concurring for cpu with the application threads, 
assuming the application utilizes all cpus for application threads.
Generating bigger code obviously will bring the application faster into this
situation.

Please, as this is a compiler issue, it should be discussed on hotspot-compiler-dev.

Best regards,
  Goetz.

> -----Original Message-----
> From: Kazunori Ogata [mailto:OGATAK at jp.ibm.com]
> Sent: Freitag, 20. Oktober 2017 08:32
> To: Lindenmaier, Goetz <goetz.lindenmaier at sap.com>
> Cc: hotspot-dev at openjdk.java.net; Doerr, Martin <martin.doerr at sap.com>;
> ppc-aix-port-dev at openjdk.java.net
> Subject: RE: 8188131: [PPC] Increase inlining thresholds to the same as other
> platforms
> 
> Hi Goetz,
> 
> Thank you for your comment.  OK, I'll evaluate the patch more by comparing
> the minimum code cache sizes and the performance on the cache size.
> 
> It is helpful if you could explain what is the difference of the JIT
> behavior when the code cache is large enough and when it is the minimum
> size.  It seems almost the same to me because all the methods that needed
> to be compiled should be compiled in both cases, but I may miss something.
> 
> 
> By the way, the benchmark I confirmed performance improvement was TPC-
> DS
> q96, but I measured the code cache size of SPECjbb2015 by my mistake. I'll
> compare the minimum code cache sizes and the performance of both
> benchmarks, as this patch will affect all applications.
> 
> 
> Regards,
> Ogata
> 
> 
> 
> From:   "Lindenmaier, Goetz" <goetz.lindenmaier at sap.com>
> To:     Kazunori Ogata <OGATAK at jp.ibm.com>, "Doerr, Martin"
> <martin.doerr at sap.com>
> Cc:     "ppc-aix-port-dev at openjdk.java.net"
> <ppc-aix-port-dev at openjdk.java.net>, "hotspot-dev at openjdk.java.net"
> <hotspot-dev at openjdk.java.net>
> Date:   2017/10/19 20:03
> Subject:        RE: 8188131: [PPC] Increase inlining thresholds to the
> same as other platforms
> 
> 
> 
> Hi Kazunori,
> 
> To me, this seems to be a very large increase.
> Considering that not only the required code cache size but also the
> compiler cpu time will increase in this magnitude, this seems to be
> a rather risky step that should be tested for its benefits on systems
> that are highly contended.
> 
> In this case, you probably had enough space in the code cache so that
> no recompilation etc. happened.
> 
> To further look at this I could think of
> 1. finding the minimal code cache size with the old flags where
>    the JIT is not disabled
> 2. finding the same size for the new flag settings
>    --> How much more is needed for the new settings?
> 
> Then you should compare the performance with the bigger
> code cache size for both, and see whether there still is performance
> improvement, or whether it's eaten up by more compile time.
> I.e. you should have a setup where compiler threads and application
> threads compete for the available CPUs.
> 
> What do you think?
> 
> Best regards,
>   Goetz.
> 
> > -----Original Message-----
> > From: hotspot-dev [mailto:hotspot-dev-bounces at openjdk.java.net] On
> > Behalf Of Kazunori Ogata
> > Sent: Donnerstag, 19. Oktober 2017 08:43
> > To: Doerr, Martin <martin.doerr at sap.com>
> > Cc: ppc-aix-port-dev at openjdk.java.net; hotspot-dev at openjdk.java.net
> > Subject: RE: 8188131: [PPC] Increase inlining thresholds to the same as
> other
> > platforms
> >
> > Hi Martin,
> >
> > Thank you for your comment.  I checked the code cache size by running
> > SPECjbb2015 (composite mode, i.e., single JVM mode, heap size is 31GB).
> >
> > The used code cache size was increased by 4.5MB from 41982Kb to 47006Kb
> > (+12%).  Is the increase too large?
> >
> >
> > The raw output of -XX:+PrintCodeCache are:
> >
> > === Original ===
> > CodeHeap 'non-profiled nmethods': size=652480Kb used=13884Kb
> > max_used=13884Kb free=638595Kb
> >  bounds [0x00001000356f0000, 0x0000100036480000, 0x000010005d420000]
> > CodeHeap 'profiled nmethods': size=652480Kb used=26593Kb
> > max_used=26593Kb
> > free=625886Kb
> >  bounds [0x000010000d9c0000, 0x000010000f3c0000, 0x00001000356f0000]
> > CodeHeap 'non-nmethods': size=5760Kb used=1505Kb max_used=1559Kb
> > free=4254Kb
> >  bounds [0x000010000d420000, 0x000010000d620000, 0x000010000d9c0000]
> >  total_blobs=16606 nmethods=10265 adapters=653
> >  compilation: enabled
> >
> >
> > === Modified (webrev.00) ===
> > CodeHeap 'non-profiled nmethods': size=652480Kb used=18516Kb
> > max_used=18516Kb free=633964Kb
> >  bounds [0x0000100035730000, 0x0000100036950000, 0x000010005d460000]
> > CodeHeap 'profiled nmethods': size=652480Kb used=26963Kb
> > max_used=26963Kb
> > free=625516Kb
> >  bounds [0x000010000da00000, 0x000010000f460000, 0x0000100035730000]
> > CodeHeap 'non-nmethods': size=5760Kb used=1527Kb max_used=1565Kb
> > free=4232Kb
> >  bounds [0x000010000d460000, 0x000010000d660000, 0x000010000da00000]
> >  total_blobs=16561 nmethods=10295 adapters=653
> >  compilation: enabled
> >
> >
> > Regards,
> > Ogata
> >
> >
> >
> >
> > From:   "Doerr, Martin" <martin.doerr at sap.com>
> > To:     Kazunori Ogata <OGATAK at jp.ibm.com>, "hotspot-
> > dev at openjdk.java.net"
> > <hotspot-dev at openjdk.java.net>, "ppc-aix-port-dev at openjdk.java.net"
> > <ppc-aix-port-dev at openjdk.java.net>
> > Date:   2017/10/18 19:43
> > Subject:        RE: 8188131: [PPC] Increase inlining thresholds to the
> > same as other platforms
> >
> >
> >
> > Hi Ogata,
> >
> > sorry for the delay. I had missed this one.
> >
> > The change looks feasible to me.
> >
> > It may only impact the utilization of the Code Cache. Can you evaluate
> > that (e.g. by running large benchmarks with -XX:+PrintCodeCache)?
> >
> > Thanks and best regards,
> > Martin
> >
> >
> > -----Original Message-----
> > From: hotspot-dev [mailto:hotspot-dev-bounces at openjdk.java.net] On
> > Behalf
> > Of Kazunori Ogata
> > Sent: Freitag, 29. September 2017 08:42
> > To: hotspot-dev at openjdk.java.net; ppc-aix-port-dev at openjdk.java.net
> > Subject: RFR: 8188131: [PPC] Increase inlining thresholds to the same as
> > other platforms
> >
> > Hi all,
> >
> > Please review a change for JDK-8188131.
> >
> > Bug report:
> > https://urldefense.proofpoint.com/v2/url?u=https-
> > 3A__bugs.openjdk.java.net_browse_JDK-
> > 2D8188131&d=DwIFAg&c=jf_iaSHvJObTbx-siA1ZOg&r=p-
> >
> FJcrbNvnCOLkbIdmQ2tigCrcpdU77tlI2EIdaEcJw&m=ExKSiZAany_n7vS453MD
> > 73lAZxkNhGsrlDkk-
> > YUYORQ&s=ic27Fb2_vyTSsUAPraEI89UDJy9cbodGojvMw9DNHiU&e=
> >
> > Webrev:
> > https://urldefense.proofpoint.com/v2/url?u=http-
> > 3A__cr.openjdk.java.net_-
> > 7Ehorii_8188131_webrev.00_&d=DwIFAg&c=jf_iaSHvJObTbx-
> siA1ZOg&r=p-
> >
> FJcrbNvnCOLkbIdmQ2tigCrcpdU77tlI2EIdaEcJw&m=ExKSiZAany_n7vS453MD
> > 73lAZxkNhGsrlDkk-YUYORQ&s=xS8PbLyuVtbOBRDMIB-
> > i9r6lTggpGH3Np8kmONkkMAg&e=
> >
> >
> > This change increases the default values of FreqInlineSize and
> > InlineSmallCode in ppc64 to 325 and 2500, respectively.  These values
> are
> > the same as aarch64.  The performance of TPC-DS Q96 was improved by
> > about
> > 6% with this change.
> >
> >
> > Regards,
> > Ogata
> >
> >
> >
> 
> 
> 