日志 - 高并发的情况下小小的日志打印会严重影响到性能

"http-saoma%2F192.168.6.162-8097-132" daemon prio=10 tid=0x00002aaab88e4800 nid=0x2c8e runnable [0x0000000045274000]
   java.lang.Thread.State: BLOCKED
    at java.lang.Throwable.getStackTraceElement(Native Method)
    at java.lang.Throwable.getOurStackTrace(Throwable.java:591)
    - locked <0x00000007691390d0> (a java.lang.Throwable)
    at java.lang.Throwable.getStackTrace(Throwable.java:582)
    at sun.reflect.GeneratedMethodAccessor29.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at org.apache.log4j.spi.LocationInfo.<init>(LocationInfo.java:139)
    at org.apache.log4j.spi.LoggingEvent.getLocationInformation(LoggingEvent.java:253)
    at org.apache.log4j.helpers.PatternParser$LocationPatternConverter.convert(PatternParser.java:500)
    at org.apache.log4j.helpers.PatternConverter.format(PatternConverter.java:65)
    at org.apache.log4j.PatternLayout.format(PatternLayout.java:506)
    at org.apache.log4j.WriterAppender.subAppend(WriterAppender.java:310)
    at org.apache.log4j.DailyRollingFileAppender.subAppend(DailyRollingFileAppender.java:369)
    at org.apache.log4j.WriterAppender.append(WriterAppender.java:162)
    at org.apache.log4j.AppenderSkeleton.doAppend(AppenderSkeleton.java:251)
    - locked <0x0000000780fb1e00> (a org.apache.log4j.DailyRollingFileAppender)
    at org.apache.log4j.helpers.AppenderAttachableImpl.appendLoopOnAppenders(AppenderAttachableImpl.java:66)
    at org.apache.log4j.Category.callAppenders(Category.java:206)
    - locked <0x00000007800020a0> (a org.apache.log4j.spi.RootLogger)
    at org.apache.log4j.Category.forcedLog(Category.java:391)
    at org.apache.log4j.Category.log(Category.java:856)
    at org.slf4j.impl.Log4jLoggerAdapter.error(Log4jLoggerAdapter.java:

String s;
// Protect against multiple access to sw.
synchronized(sw) {
t.printStackTrace(pw);
s = sw.toString();
sw.getBuffer().setLength(0);
}
//System.out.println("s is ["+s+"].");
int ibegin, iend;
// Given the current structure of the package, the line
// containing "org.apache.log4j.Category." should be printed just
// before the caller.
// This method of searching may not be fastest but it's safer
// than counting the stack depth which is not guaranteed to be
// constant across JVM implementations.
ibegin = s.lastIndexOf(fqnOfCallingClass);