Messages in this thread | | | Subject | Re: [RFC] The New and Improved Logdev (now with kprobes!) | From | Daniel Walker <> | Date | Thu, 05 Oct 2006 11:49:06 -0700 |
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On Thu, 2006-10-05 at 14:38 -0400, Steven Rostedt wrote: > On Thu, 5 Oct 2006, Daniel Walker wrote: > > > On Thu, 2006-10-05 at 14:09 -0400, Steven Rostedt wrote: > > > > > > > > My problem with using a timestamp, is that I ran logdev on too many archs. > > > So I need to have a timestamp that I can get to that is always reliable. > > > How does LTTng get the time for different archs? Does it have separate > > > code for each arch? > > > > > > > I just got done updating a patchset that exposes the clocksources from > > generic time to take low level time stamps.. But even without that you > > can just call gettimeofday() directly to get a timestamp . > > > > unless you're tracing something that his holding the xtime_lock ;-)
That's part of the reason for the changes that I made to the clocksource API . It makes it so instrumentation, with other things, can generically read a low level cycle clock. Like on PPC you would read the decrementer, and on x86 you would read the TSC . However, the application has no idea what it's reading.
I submitted one version to LKML already, but I'm planning to submit another version shortly.
Daniel
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