From: compudj Date: Wed, 21 Jan 2009 22:12:14 +0000 (+0000) Subject: ust update X-Git-Tag: v0.12.20~251 X-Git-Url: http://git.lttng.org./?a=commitdiff_plain;h=14b9349e991bb72ec9a322e6a789a2a70d421e1b;hp=7af3a2646a332759fe7b1d888aae4515eb12b075;p=lttv.git ust update git-svn-id: http://ltt.polymtl.ca/svn@3238 04897980-b3bd-0310-b5e0-8ef037075253 --- diff --git a/trunk/lttv/doc/developer/ust.txt b/trunk/lttv/doc/developer/ust.txt index 03799389..a379e553 100644 --- a/trunk/lttv/doc/developer/ust.txt +++ b/trunk/lttv/doc/developer/ust.txt @@ -31,3 +31,12 @@ The application may also spontaneously provide information to the pipe: In addition, the tracing control application should be notified when the application exits (to save the content of buffers if the application is crashing). Such notification may be obtained through utrace. + +This tracing scheme plans to use a direct function call to tracing into buffers +mapped in user-space. This should be an order of magnitude faster than the +current Dtrace implementation (c.f. +https://ltt.polymtl.ca/tracingwiki/index.php/DTrace) which uses a breakpoint to +perform both dynamic and static user-space tracing. Performance comparison of +a function call vs the int3 approach is available at +http://sourceware.org/ml/systemtap/2006-q3/msg00793.html (see "Conclusion"). +