RFR(XL): 8199712: Flight Recorder

Magnus Ihse Bursie magnus.ihse.bursie at oracle.com
Thu Apr 26 09:45:02 UTC 2018

On 2018-04-25 13:06, Erik Gahlin wrote:
> Greetings,
> Could I have a review of 8199712: Flight Recorder
> As mentioned in the preview [1] the tracing backend has been removed. 
> Event metadata has been consolidated into a single XML file and event 
> classes are now generated by GenerateJfrFiles.java.
> Tests have been run on Linux-x64, Windows-x64 and MaxOSX-x64.
> For details about the feature, see the JEP:
> https://bugs.openjdk.java.net/browse/JDK-8193393
> Webrev:
> http://cr.openjdk.java.net/~egahlin/8199712.0/
Hi Erik,

When posting build changes (files in "make/*"), please always include 
build-dev. Thanks! :-)

This review is for build changes only.

* make/RunTestsPrebuiltSpec.gmk: This file has only a copyright year 
change. It can be reverted.

* make/copy/Copy-jdk.jfr.gmk:
COPY_HOTSPOT_TRACE_FILES should be renamed to something like 

The second part is better off rewritten using SetupCopyFiles.

Something like this, written on-the-fly, so might not work. (Email me 
privately if it does not work and you need help.)

JFR_CONF_DIR := $(TOPDIR)/src/jdk.jfr/share/conf/jfr

$(eval $(call SetupCopyFiles, COPY_JFR_CONF, \
   DEST := $(LIB_DST_DIR)/jfr, \
   FILES := $(wildcard $(JFR_CONF_DIR)/*.jfc), \
   FLATTEN := true, \


* make/autoconf/hotspot.m4:
It's a bit unfortunate with the --enable-jfr option. Ideally, this 
should be handled only as a JVM feature (--with-jvm-features=jfr). Try 
this piece of code instead: (Not tested, but should work.)

diff --git a/make/autoconf/hotspot.m4 b/make/autoconf/hotspot.m4
--- a/make/autoconf/hotspot.m4
+++ b/make/autoconf/hotspot.m4
@@ -26,7 +26,7 @@
  # All valid JVM features, regardless of platform
  VALID_JVM_FEATURES="compiler1 compiler2 zero minimal dtrace jvmti jvmci \
      graal vm-structs jni-check services management all-gcs nmt cds \
-    static-build link-time-opt aot"
+    static-build link-time-opt aot jfr"

  # All valid JVM variants
  VALID_JVM_VARIANTS="server client minimal core zero custom"
@@ -313,6 +313,11 @@
      AC_MSG_ERROR([Specified JVM feature 'vm-structs' requires feature 

+  # Enable JFR by default, except on linux-sparcv9 and on minimal.
+  if test "x$OPENJDK_TARGET_OS" != xlinux || test 
"x$OPENJDK_TARGET_CPU" != xsparcv9; then
+  fi
    # Turn on additional features based on other parts of configure
    if test "x$INCLUDE_DTRACE" = "xtrue"; then

Otherwise, build changes look good!


> Bug:
> https://bugs.openjdk.java.net/browse/JDK-8199712
> [1] 
> http://mail.openjdk.java.net/pipermail/hotspot-dev/2018-April/031359.html
> Thanks
> Erik and Markus

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