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Re: Unified tracing buffer
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