Messages in this thread Patch in this message |  | | | From | Don Zickus <> | | Subject | [PATCH] watchdog: Quiet down the boot messages | | Date | Thu, 7 Jun 2012 22:15:36 -0400 |
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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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