我正在使用 Ubuntu 18.04 并运行perf stat命令以获取有关应用程序的各种硬件事件的一些信息。我注意到做sudo perf stat --interval-print 1，我得到一个错误说print interval must be >= 10ms。但是，在 Ubuntu 和 Linux 手册页（https://man7.org/linux/man-pages/man1/perf-stat.1.html）中，它提到最小值为interval-print1ms。通过这样做uname -r，我的内核版本为：4.15.0-158-generic，并且我已经按照此处的说明安装了该工具：https ://askubuntu.com/a/578618/1000263 。
关于如何perf stat在我的机器上以 1 毫秒的间隔时间运行命令的任何帮助将非常有帮助和感激。如果需要更多信息，请告诉我。
我尝试了几种安装方法openjdk，这是我安装时得到的：java -version
openjdk version "11.0.4" 2019-07-16
OpenJDK Runtime Environment (build 11.0.4+11-post-Ubuntu-1ubuntu218.04.3)
OpenJDK 64-Bit Server VM (build 11.0.4+11-post-Ubuntu-1ubuntu218.04.3, mixed mode, sharing)
但是当我执行 javac -version 时，它说找不到 javac。我执行以下操作：sudo apt-get install default-jre
The following packages have unmet dependencies:
default-jre : Depends: default-jre-headless (= 2:1.10-63ubuntu1~02) but 2:1.11-68ubuntu1~18.04.1 is to be installed
Depends: openjdk-11-jre but it is not going to be installed
E: Unable to correct problems, you have held broken packages.
然后：sudo apt-get install default-jdk
default-jdk : Depends: default-jre (= 2:1.10-63ubuntu1~02) but it is not going to be installed
Depends: default-jdk-headless (= 2:1.10-63ubuntu1~02) but it is not going to be installed
Depends: openjdk-11-jdk but it is not going to be installed
E: Unable to correct problems, you have held broken packages.
然后：sudo update-alternatives --config java
替代 java 有 2 种选择（提供 /usr/bin/java）。
Selection Path Priority Status
------------------------------------------------------------
* 0 /usr/lib/jvm/java-11-openjdk-amd64/bin/java 1111 auto mode
1 /usr/lib/jvm/java-11-openjdk-amd64/bin/java 1111 manual mode
2 /usr/lib/jvm/java-8-openjdk-amd64/jre/bin/java 1081 manual mode
如何解决这些问题并正确安装 java 和 javac？