Author: seb Date: Wed Jan 24 19:01:40 2007 New Revision: 1280 Modified: logback/trunk/logback-site/src/site/xdocTemplates/manual/architecture.xml Log: corrected figures Modified: logback/trunk/logback-site/src/site/xdocTemplates/manual/architecture.xml ============================================================================== --- logback/trunk/logback-site/src/site/xdocTemplates/manual/architecture.xml (original) +++ logback/trunk/logback-site/src/site/xdocTemplates/manual/architecture.xml Wed Jan 24 19:01:40 2007 @@ -1160,7 +1160,7 @@ When logging is turned off entirely, the cost of a log request consists of a method invocation plus an integer comparison. On a 3.2Ghz Pentium D machine this cost is typically -in the 500 - 600 nanosecond range. +around 20 nanoseconds. </p> <p> @@ -1204,22 +1204,17 @@ <h4>2. The performance of deciding whether to log or not to log when logging is turned on.</h4> <p> -This is essentially the performance of walking the logger hierarchy. -When logging is turned on, logback still needs to compare the level of the -log request with the level of the request logger. However, loggers may not have an -assigned level; they can inherit them from the logger hierarchy. Thus, before -inheriting a level, the logger may need to search its ancestors. +In logback, there is no need to walk the whole logger hierarchy. A logger knows +its effective level (that is, its level, once level inheritance has been +taken into consideration) when it is created. Should the level of a parent logger +be changed, then all child loggers will be contacted and handle the change. Thus, before +accepting or denying a request based on the effective level, the logger does not need +to search its ancestors. </p> <p> -There has been a serious effort to make this hierarchy walk to be as fast as -possible. For example, child loggers link only to their existing ancestors. -This significantly improves the speed of the walk, especially in <em>sparse</em> hierarchies. -</p> - -<p> -The cost of walking the hierarchy is typically 2 times slower than just -checking whether logging is turned off entirely. +Given this situation, it takes the same time to decide whether to log or not when logging +is turned on as it takes when logging is turned off. </p> <h4>3. Actual logging (formatting and writing to the output device)</h4> @@ -1229,7 +1224,7 @@ target destination. Here again, a serious effort was made to make layouts (formatters) perform as quickly as possible. The same is true for appenders. The typical cost of actually logging is -about 10 to 15 microseconds when logging to a file on the local machine. +about 9 to 12 microseconds when logging to a file on the local machine. It goes up to 1 millisecond when logging to a database on a remote server. </p>