Firefox/Projects/Startup Time Improvements/joelr notes
Intro
I'm trying to figure out where Firefox startup time goes, up to the return from BrowserStartup (Javascript function). I'm also manipulating DTrace into telling me where time is going, without making any assumptions.
Current status
August 21, 2009
August 24, 2009
vtimestamp measures CPU time of the current thread, excluding IO and DTrace overhead. timestamp can still be used for deltas but the goal is to use as few pid$target probes as possible as they affect timestamp when dtrace has to switch between kernel and userland. io and syscall providers are fast and run in the kernel.
My DTrace scripts live here.
Have you seen this kind of error before?
dtrace: error on enabled probe ID 27 (ID 22130: pid34547:libSystem.B.dylib:dlopen:entry): invalid address (0x2ac204) in action #1 at DIF offset 28 dtrace: error on enabled probe ID 2 (ID 22782: pid34547:dyld:dlopen:entry): invalid address (0x2ac204) in action #1 at DIF offset 28
More likely than not, you are using copyinstr on memory that hasn't been paged in yet. Try saving the pointer on entry and doing the copying on return or later.