Hi Remko. Thanks for the reply. I changed includeLocation to false and re-run the test. But it didn't change better. QPS is still about 5000.
I found user occupies CPU for about 70% when I run sync log4j1 and sync log4j2. But when I run async log4j2, it's only about 30% and system occupies for about 70%. All of them(include sync log4j2 and async log4j2) are under very high load average. Are these normal numbers? On Sun, Oct 11, 2015 at 7:56 PM, Remko Popma <remko.po...@gmail.com> wrote: > See also http://logging.apache.org/log4j/2.x/manual/async.html#Location > and > > http://logging.apache.org/log4j/2.x/manual/async.html#Throughput_of_Logging_With_Location_includeLocationtrue > > On Sun, Oct 11, 2015 at 1:54 PM, Remko Popma <remko.po...@gmail.com> > wrote: > > > The problem with the strange performance result is because of the > > configuration: > > You have includeLocation=true. This will force Log4j to take a snapshot > of > > the stack and is very slow. > > > > Your layouts do not actually use this information, and this explains why > > synchronous logging is faster: synchronous logging will _only_ take a > > snapshot of the stack when the layout needs it. In your case this is > never, > > so you get fast performance. > > > > The solution is to change your config to > > <Root level="info" includeLocation="false"> > > > > If you test this with async loggers you should see a performance > > improvement immediately. > > > > On Sun, Oct 11, 2015 at 12:21 PM, Strong Su <lovelo...@gmail.com> wrote: > > > >> My log4j2 sync configuration is: > >> > >> <?xml version="1.0" encoding="UTF-8"?> > >> <Configuration> > >> <Appenders> > >> <!-- Async Loggers will auto-flush in batches, so switch off > >> immediateFlush. --> > >> <File name="File" fileName="{PATH}/a.log" > >> immediateFlush="false" append="false"> > >> <PatternLayout pattern="%d %-5p [%c{2}] %m%n"/> > >> </File> > >> <Console name="STDOUT" target="SYSTEM_OUT"> > >> <PatternLayout pattern="%d %-5p [%c{2}] %m%n"/> > >> </Console> > >> </Appenders> > >> > >> <Loggers> > >> <Root level="info" includeLocation="true"> > >> <AppenderRef ref="File"/> > >> <AppenderRef ref="STDOUT"/> > >> </Root> > >> </Loggers> > >> > >> </Configuration> > >> > >> And async configuration change <Root> to <AsyncRoot> > >> > >> On Sun, Oct 11, 2015 at 10:51 AM, Remko Popma <remko.po...@gmail.com> > >> wrote: > >> > >> > Can you post your log4j2 configuration? > >> > > >> > Sent from my iPhone > >> > > >> > > On 2015/10/10, at 21:58, Strong Su <lovelo...@gmail.com> wrote: > >> > > > >> > > I insert a log in a http request function on server side. And I > start > >> > > requests continually on client side through hundreds of threads. > >> > > I measure the performance through QPS because server has to print a > >> log > >> > > whenever it receive a request. The time delayed by logging will > >> influence > >> > > QPS heavily. > >> > > When I didn't insert a log in the request function, QPS was about > >> 20000. > >> > > When I inserted a log4j1 log, QPS was about 10000. > >> > > When I inserted a log4j2 sync log, QPS was about 18000. > >> > > But when I inserted a log4j2 asycn log, QPS was only about 5000. > >> > > > >> > >> On Sat, Oct 10, 2015 at 8:34 PM, Remko Popma < > remko.po...@gmail.com> > >> > wrote: > >> > >> > >> > >> How did you measure the good performance (with sync logging) and > the > >> bad > >> > >> performance (with async)? What happens exactly when "it turns > >> terrible"? > >> > >> > >> > >>> On Saturday, 10 October 2015, Strong Su <lovelo...@gmail.com> > >> wrote: > >> > >>> > >> > >>> Hello everyone, > >> > >>> I'm still testing log4j2 on our projects. > >> > >>> When using it, I find it has a beautiful performance when using > sync > >> > >>> log4j2. > >> > >>> But it turns terrible when I add -DLog4jContextSelector or change > >> > <root> > >> > >> to > >> > >>> <AsyncRoot> in log4j2.xml to use async log4j2. > >> > >>> I don't even have a clue on explaining this.What could cause this > >> > bizarre > >> > >>> problem? > >> > >>> > >> > >>> Thank you. > >> > >>> Best regards, > >> > >>> Dylan Su > >> > >> > >> > > >> > --------------------------------------------------------------------- > >> > To unsubscribe, e-mail: log4j-user-unsubscr...@logging.apache.org > >> > For additional commands, e-mail: log4j-user-h...@logging.apache.org > >> > > >> > > >> > > > > >
