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    SubjectRe: [PATCH 1/2] perf tools: Add reference timestamp to perf header

    On 12/13/10 10:57, Peter Zijlstra wrote:
    >> What about creating a PERF_RECORD_TIME and generate an event when the
    >> counter is opened? It contains a PERF_SAMPLE_TIME and say
    >> PERF_SAMPLE_TOD (time-of-day)? We're not sending rockets to saturn; we
    >> just need the timestamps to match other log files.
    > That's similar to the first thing I proposed. The problem is with long
    > record sessions your drift can become quite significant, then when you
    > merge sort your other log events stuff can get out of order. Which can
    > lead to some serious head-scratching..

    Gotcha. Missed that in the flury of emails.

    Arnaldo: Are you ok with this option? This should append mode as well.

    > Another problem with this approach is things like flight-recorder mode
    > where you constantly over-write your old data, you'd have to build some
    > trigger to always output a new record before you over-write the old one,
    > so there's always one consistent record around. Drift is an even more
    > serious problem here since flight-record more could be running for days
    > before (if ever) you dump it.

    Ok. I was not aware flight-recorder mode was an option today.



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