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    Subject[PATCH] watchdog: Quiet down the boot messages
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    A bunch of bugzillas have complained how noisy the nmi_watchdog is during
    boot-up especially with its expected failure cases (like virt and bios
    resource contention).

    This is my attempt to quiet them down and keep it less confusing for the end
    user. What I did is print the message for cpu0 and save it for future
    comparisions. If future cpus have an identical message as cpu0, then don't
    print the redundant info. However, if a future cpu has a different message,
    happily print that loudly.

    Before the change, you would see something like:

    ..TIMER: vector=0x30 apic1=0 pin1=2 apic2=-1 pin2=-1
    CPU0: Intel(R) Core(TM)2 Quad CPU Q9550 @ 2.83GHz stepping 0a
    Performance Events: PEBS fmt0+, Core2 events, Intel PMU driver.
    ... version: 2
    ... bit width: 40
    ... generic registers: 2
    ... value mask: 000000ffffffffff
    ... max period: 000000007fffffff
    ... fixed-purpose events: 3
    ... event mask: 0000000700000003
    NMI watchdog enabled, takes one hw-pmu counter.
    Booting Node 0, Processors #1
    NMI watchdog enabled, takes one hw-pmu counter.
    #2
    NMI watchdog enabled, takes one hw-pmu counter.
    #3 Ok.
    NMI watchdog enabled, takes one hw-pmu counter.
    Brought up 4 CPUs
    Total of 4 processors activated (22607.24 BogoMIPS).

    After the change, it is simlified to:

    ..TIMER: vector=0x30 apic1=0 pin1=2 apic2=-1 pin2=-1
    CPU0: Intel(R) Core(TM)2 Quad CPU Q9550 @ 2.83GHz stepping 0a
    Performance Events: PEBS fmt0+, Core2 events, Intel PMU driver.
    ... version: 2
    ... bit width: 40
    ... generic registers: 2
    ... value mask: 000000ffffffffff
    ... max period: 000000007fffffff
    ... fixed-purpose events: 3
    ... event mask: 0000000700000003
    NMI watchdog enabled, takes one hw-pmu counter.
    Booting Node 0, Processors #1 #2 #3 Ok.
    Brought up 4 CPUs

    Reported-and-tested-by: Nathan Zimmer <nzimmer@sgi.com>
    Signed-off-by: Don Zickus <dzickus@redhat.com>
    ---
    kernel/watchdog.c | 20 +++++++++++++++++++-
    1 files changed, 19 insertions(+), 1 deletions(-)

    diff --git a/kernel/watchdog.c b/kernel/watchdog.c
    index e5e1d85..79ff671 100644
    --- a/kernel/watchdog.c
    +++ b/kernel/watchdog.c
    @@ -377,6 +377,14 @@ static int watchdog_nmi_enable(int cpu)
    struct perf_event_attr *wd_attr;
    struct perf_event *event = per_cpu(watchdog_ev, cpu);

    + /*
    + * People like the simple clean cpu node info
    + * on boot. Simplify the noise from the watchdog
    + * by only printing messages that are different than
    + * what cpu0 displayed
    + */
    + static unsigned long err0 = 0;
    +
    /* is it already setup and enabled? */
    if (event && event->state > PERF_EVENT_STATE_OFF)
    goto out;
    @@ -390,11 +398,21 @@ static int watchdog_nmi_enable(int cpu)

    /* Try to register using hardware perf events */
    event = perf_event_create_kernel_counter(wd_attr, cpu, NULL, watchdog_overflow_callback, NULL);
    +
    + /* save cpu0 error for future comparision */
    + if (!cpu)
    + err0 = (IS_ERR(event) ? PTR_ERR(event) : 0);
    +
    if (!IS_ERR(event)) {
    - pr_info("enabled, takes one hw-pmu counter.\n");
    + /* only print for cpu0 or different than cpu0 */
    + if (!cpu || err0)
    + pr_info("enabled, takes one hw-pmu counter.\n");
    goto out_save;
    }

    + /* skip displaying the same error again */
    + if ((PTR_ERR(event) == err0) && cpu)
    + return PTR_ERR(event);

    /* vary the KERN level based on the returned errno */
    if (PTR_ERR(event) == -EOPNOTSUPP)
    --
    1.7.7.6


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