Thanks, Steve. Virtually, what I want is: tracing_on(1), snapshort, traces..., snapshot, tracing_on(0). If I understand right, I need the new feature "snapshot" in ftrace. But, it seems snapshot and ftrace are separated, which does not satisfy my need. What is your suggestion? Yuyang -----Original Message----- From: linux-trace-users-owner@xxxxxxxxxxxxxxx [mailto:linux-trace-users-owner@xxxxxxxxxxxxxxx] On Behalf Of Steven Rostedt Sent: Thursday, September 12, 2013 11:38 AM To: Du, Yuyang Cc: linux-trace-users@xxxxxxxxxxxxxxx Subject: Re: Query: is it possible to trace at exactly start and end time of tracing On Thu, 12 Sep 2013 03:16:00 +0000 "Du, Yuyang" <yuyang.du@xxxxxxxxx> wrote: > Because I want to save start and end snapshots of some state. > I'm not exactly sure what you want. You can use the new "snapshot" feature (available since 3.10) and save the start and stop of a state without the need of tracing it. echo 1 > /sys/kernel/debug/tracing/snapshot cat /sys/kernel/debug/tracing/snapshot -- Steve -- To unsubscribe from this list: send the line "unsubscribe linux-trace-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-trace-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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