fix: timer/trace: Improve timer tracing (v5.2)
authorMichael Jeanson <mjeanson@efficios.com>
Tue, 21 May 2019 20:33:10 +0000 (16:33 -0400)
committerMathieu Desnoyers <mathieu.desnoyers@efficios.com>
Wed, 22 May 2019 14:49:07 +0000 (10:49 -0400)
commit23228f26b4634dece2f3ef74536c923b3cea9c8b
tree3aeadf7ba49ba595ae228736b4b99653602e6aae
parentbf6a783825b46345d8f4616d47e12f0bcd2ce89d
fix: timer/trace: Improve timer tracing (v5.2)

See upstream commit:

  commit f28d3d5346e97e60c81f933ac89ccf015430e5cf
  Author: Anna-Maria Gleixner <anna-maria@linutronix.de>
  Date:   Thu Mar 21 13:09:21 2019 +0100

    timer/trace: Improve timer tracing

    Timers are added to the timer wheel off by one. This is required in
    case a timer is queued directly before incrementing jiffies to prevent
    early timer expiry.

    When reading a timer trace and relying only on the expiry time of the timer
    in the timer_start trace point and on the now in the timer_expiry_entry
    trace point, it seems that the timer fires late. With the current
    timer_expiry_entry trace point information only now=jiffies is printed but
    not the value of base->clk. This makes it impossible to draw a conclusion
    to the index of base->clk and makes it impossible to examine timer problems
    without additional trace points.

    Therefore add the base->clk value to the timer_expire_entry trace
    point, to be able to calculate the index the timer base is located at
    during collecting expired timers.

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
instrumentation/events/lttng-module/timer.h
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