Integrated: 8267517: async logging for stdout and stderr

[Xin Liu]

On Wed, 27 Oct 2021 08:22:12 GMT, Xin Liu <xliu at openjdk.org> wrote:

> This patch refactors LogFileStreamOutput so stdout/stderr can support support -Xlog:async.
> 
> With  `-Xlog:all=trace:stdout`, the helloworld in Java outputs 16520 log entries to stdout.  We are see that the wall time reduces from  84.138ms to 72.914ms, or the throughput increases 15% because of async logging.
> 
> 
> $perf stat -r 300 ./build/linux-x86_64-server-release/images/jdk/bin/java -Xlog:all=trace:stdout -Xlog:async -XX:AsyncLogBufferSize=48M HelloWorld > /dev/null
> 
>  Performance counter stats for './build/linux-x86_64-server-release/images/jdk/bin/java -Xlog:all=trace:stdout -Xlog:async -XX:AsyncLogBufferSize=48M HelloWorld' (300 runs):
> 
>             107.21 msec task-clock                #    1.470 CPUs utilized            ( +-  0.17% )
>              2,681      context-switches          #    0.025 M/sec                    ( +-  0.32% )
>                  1      cpu-migrations            #    0.011 K/sec                    ( +-  4.56% )
>              4,006      page-faults               #    0.037 M/sec                    ( +-  0.01% )
> ...
>           0.072914 +- 0.000126 seconds time elapsed  ( +-  0.17% )
> 
>  Performance counter stats for './build/linux-x86_64-server-release/images/jdk/bin/java -Xlog:all=trace:stdout -XX:AsyncLogBufferSize=48M HelloWorld' (300 runs):
> 
>              88.04 msec task-clock                #    1.046 CPUs utilized            ( +-  0.10% )
>                310      context-switches          #    0.004 M/sec                    ( +-  0.31% )
>                  1      cpu-migrations            #    0.008 K/sec                    ( +-  5.07% )
>              4,004      page-faults               #    0.045 M/sec                    ( +-  0.01% )
> ...
>           0.084138 +- 0.000111 seconds time elapsed  ( +-  0.13% )
> 
> 
> The easiest test of stdout with AsyncLogging is to use tty and XOFF Ctrl^s. Java applications with UL to stdout were blocked by Ctrl-s. The entire java process will be frozen.  -Xlog:async now cover both stdout and stderr. It can circumvent this issue.  
> 
> Add a new jtreg to cover a scenario that unified logging with -Xlog:async will not be frozen even when stdout is blocked.

This pull request has now been integrated.

Changeset: 7aff03ae
Author:    Xin Liu <xliu at openjdk.org>
URL:       https://git.openjdk.java.net/jdk/commit/7aff03aee1a5cd70638d8bbafeb7765bc7beea45
Stats:     129 lines in 7 files changed: 92 ins; 11 del; 26 mod

8267517: async logging for stdout and stderr

Reviewed-by: dholmes, ysuenaga

-------------

PR: https://git.openjdk.java.net/jdk/pull/6132