Messages in this thread | | | Date | Tue, 23 Sep 2008 00:10:32 -0400 | From | Masami Hiramatsu <> | Subject | Re: Unified tracing buffer |
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Steven Rostedt wrote: > But, with that, with a global atomic counter, and the following trace: > > cpu 0: trace_point_a > cpu 1: trace_point_c > cpu 0: trace_point_b > cpu 1: trace_point_d > > > Could the event a really come after event d, even though we already hit > event b?
yes, if event c is an interrupt event :-).
cpu 0 cpu 1 hit event d hit event a log event a irq event c log event c hit event b log event b log event d
so, I think if we really need to order events, we have to stop irq right after hitting an event.
Anyway, in most case, I think it works, but as accurate as synchronized-TSC if hardware supports it.
Thank you,
-- Masami Hiramatsu
Software Engineer Hitachi Computer Products (America) Inc. Software Solutions Division
e-mail: mhiramat@redhat.com
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