Messages in this thread | | | Date | Tue, 07 May 2013 11:48:26 -0400 | From | Christopher Covington <> | Subject | Re: [RFC PATCH 0/2] ARM: Remove any correlation between IPC and BogoMips value |
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On 05/07/2013 05:08 AM, Will Deacon wrote: > On Mon, May 06, 2013 at 07:01:23PM +0100, Christopher Covington wrote: >> Hi Will, >> >> On 05/03/2013 01:35 PM, Will Deacon wrote: >>> Hi all, >>> >>> This small patch set may look a little over a month late, but there is a >>> serious reason for posting it. >>> >>> When I moved the ARM delay loop over to using the architected timers >>> rather than the CPU spinning loop (which has all the problems associated >>> with cpu frequency scaling and what-not) I thought I was doing something >>> useful for the port. However, it turns out that a surprising number of >>> people have complained, and continue to complain, about the drop in >>> their `BogoMIPs score'. >> >> Have you considered adding the old code back in, but in a form that's not at >> all referenced by the delay loop code and just calculates CPU-based bogomips? > > That seems like a lot of effort in order to preserve something that isn't > even meaningful. We might be better just zeroing the value, but then we'll > inevitably get bug reports of it being `wrong'.
If I were in to filing bug reports about bogomips values, I would be just as likely to do it for 1, 10000, 99999, and get_random_bytes(...) as for 0.
> Plus, the calibration during boot introduces a brief delay when onlining > each core whereas this can be skipped when using a constant timer.
If it were configurable, that might give people a reason to weigh whether they really cared about knowing bogomips at the cost of boot time.
Christopher
-- Employee of Qualcomm Innovation Center, Inc. Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by the Linux Foundation.
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