JDK-8080919 : Perf: SPECjb2013 critical jOPs - up to 50% regressed
  • Type: Bug
  • Component: performance
  • Sub-Component: libraries
  • Affected Version: 8u45
  • Priority: P1
  • Status: Closed
  • Resolution: Duplicate
  • OS: linux
  • CPU: x86
  • Submitted: 2015-05-22
  • Updated: 2015-05-26
  • Resolved: 2015-05-26
Related Reports
Duplicate :  
JDK-8080623 - CPU overhead in FJ due to spinning in awaitWork
Relates :  
JDK-8080623 - CPU overhead in FJ due to spinning in awaitWork
Description
SYNOPSIS:
Perf: SPECjb2013 critical jOPs - up to 50% regressed

OPERATING SYSTEM(S):
All platforms

FULL JDK VERSION(S):

jdk 8u45

DESCRIPTION:

STEPS TO REPRODUCE:
Run benchmark test SPECjbb2013 on configuration Multi-JVM (2-group).

Result obtained :
critical jOPS regression by 50%
                                              maxJOPs             critical_jOPS               hbIR_max             hbIR_settled
=============================================================================
jdk 8u25 (20140917)             28193.667                  12447                         33169                      31275
jdk 8u45 (20150410)             28110.750                    8449                         33169                      31042

Expected Result :
The regression doesn't happen.


Description: 
The regression is caused by an oracle bug change "8056248: Improve ForkJoin thread throttling". 


Proposed fix :
Comments
SPECjbb2013 relies on ForkJoin heavily, the submitted tasks varies in size and frequency and the added CPU overhead due to the added spinning caused the performance to be reduced in certain circumstances. Also please not that SPECjbb2013 jOPS are not stable due to a code defect this version, please the spec.org website.
26-05-2015