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    SubjectRE: [PATCH v2] printk: add option to print cpu id
    > -----Original Message-----
    > From: linux-kernel-owner@vger.kernel.org [mailto:linux-kernel-
    > owner@vger.kernel.org] On Behalf Of Vikram Pandita
    > Sent: Friday, August 03, 2012 2:46 PM
    > To: gregkh@linuxfoundation.org; kay@vrfy.org
    > Cc: linux-kernel@vger.kernel.org; Vikram Pandita; Mike Turquette; Vimarsh
    > Zutshi
    > Subject: [PATCH v2] printk: add option to print cpu id
    >
    > From: Vikram Pandita <vikram.pandita@ti.com>
    >
    > Introduce config option to enable CPU id reporting for printk() calls.
    >
    > Example logs with this option enabled look like:
    > [1] [ 2.328613] usbcore: registered new interface driver libusual
    > [1] [ 2.335418] usbcore: registered new interface driver usbtest
    > [1] [ 2.342803] mousedev: PS/2 mouse device common for all mice
    > [0] [ 2.352600] twl_rtc twl_rtc: Power up reset detected.
    > [0] [ 2.359191] twl_rtc twl_rtc: Enabling TWL-RTC
    > [1] [ 2.367797] twl_rtc twl_rtc: rtc core: registered twl_rtc as rtc0
    > [1] [ 2.375274] i2c /dev entries driver
    > [1] [ 2.382324] Driver for 1-wire Dallas network protocol.
    >
    > Its sometimes very useful to have printk also print the CPU Identifier
    > that executed the call. This has helped to debug various SMP issues on
    > shipping
    > products.

    Is it not better to have macros which will have wrapper to printk with required
    debug info added? E.g. cpu# in your case.
    If by default we add cupid, is it not over head in each message getting
    printed with printk?

    >
    > Known limitation is if the system gets preempted between function call and
    > actual printk, the reported cpu-id might not be accurate. But most of the
    > times its seen to give a good feel of how the N cpu's in the system are
    > getting loaded.
    >


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