Re: [PATCH] Re: boot time, process start time, and NOW time

From: john stultz (johnstul_at_us.ibm.com)
Date: 08/31/04

  • Next message: Adrian Bunk: "[2.6 patch] update Dag Brattli's email address" 
    To: george anzinger <george@mvista.com>
Date:	Tue, 31 Aug 2004 13:56:58 -0700

    On Tue, 2004-08-31 at 12:27, George Anzinger wrote:
    > Tim Schmielau wrote:
    > > On Mon, 30 Aug 2004, john stultz wrote:
    > >>On Mon, 2004-08-30 at 16:00, Tim Schmielau wrote:
    > >>
    > >>>George, please excuse my lack of understanding. What again where the
    > >>>precise reasons to have an ntp-corrected uptime?
    > >>
    > >>Ah, here's the thread with the first mention of it that I could find.
    > >>
    > >>http://www.uwsg.iu.edu/hypermail/linux/kernel/0306.1/1471.html
    >
    > As I recall the problem was that jiffies since boot was being converted to get
    > uptime base on 1/HZ = 1 jiffie. Since it is really not quite that, there was an
    > error. Using clock_monotonic seemed like the right answer as it eliminated the
    > error AND made the result consistant with get_clock(CLOCK_MONOTONIC,..).
    >
    > The alternate answer is, of course, to directly convert the elapsed jiffies.
    > The main problem with this is that this can be a BIG number and, therefor, the
    > math needs to be carefully. And, of course, it is inconsistant with
    > get_clock(), but that is a new interface...

    Hmmm. Well, I may be starting to lean in Tim's direction of pulling the
    clock_monotonic based uptime and going back to the jiffies based uptime.
    Atleast until we can make all the /proc/ output consistent.

    I just worry that it actually fixed a problem for someone, and backing
    it out would just reopen that.

    Thoughts?

    -john

    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

  • Next message: Adrian Bunk: "[2.6 patch] update Dag Brattli's email address"

    Relevant Pages

    • RE: New Linux System time proposal
      ... > to interrupt ... you read the sum of bootime, time_adj, and jiffies. ... Boot time is read from the RTC upon ... send the line "unsubscribe linux-kernel" in ...
      (Linux-Kernel)
    • Re: /proc or ps tools bug? 2.6.3, time is off
      ... Then add jiffies and divide by uptime: ... send the line "unsubscribe linux-kernel" in ...
      (Linux-Kernel)
    • Re: boot time, process start time, and NOW time
      ... while the latter is computed from "jiffies" and thus uncorrected. ... "uptime" is needed for that. ... No, that's not needed anymore. ... send the line "unsubscribe linux-kernel" in ...
      (Linux-Kernel)
    • Re: [PATCH] Re: boot time, process start time, and NOW time
      ... I may be starting to lean in Tim's direction of pulling the ... >clock_monotonic based uptime and going back to the jiffies based uptime. ... send the line "unsubscribe linux-kernel" in ...
      (Linux-Kernel)
    • Re: Uptime counter
      ... > jiffies to 64 bit. ... And I promise to release 2.0.41 before you've had 497 days of uptime ... send the line "unsubscribe linux-kernel" in ... More majordomo info at http://vger.kernel.org/majordomo-info.html ...
      (Linux-Kernel)