Messages in this thread | | | Subject | Re: [PATCH] clocksource/drivers/tango-xtal: Replace code by clocksource_mmio_init | From | Daniel Lezcano <> | Date | Tue, 17 Nov 2015 14:11:35 +0100 |
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On 11/17/2015 01:48 PM, Marc Gonzalez wrote: > On 17/11/2015 13:22, Daniel Lezcano wrote: >> On 11/13/2015 01:20 PM, Marc Gonzalez wrote: >>> On 13/11/2015 11:58, Daniel Lezcano wrote: >>> >>>> The current code to initialize, register and read the clocksource is >>>> already factored out in mmio.c via the clocksource_mmio_init function. >>>> >>>> Factor out the code with the clocksource_mmio_init function. >>> >>> The reason I didn't like clocksource_mmio_init() is because it exports >>> 4 generic accessors. >>> >>> I guess this function makes more sense when all platforms are using it, >>> in an ARCH_MULTIPLATFORM kernel. (Also the accessors are probably quite >>> small, so the waste is probably minimal.) >> >> Hi Marc, >> >> it is not clear for me if you agree with this patch or not. Can you >> clarify ? > > [ Adding rmk as the original mmio.c author ]
Good idea. Russell, the patch is https://lkml.org/lkml/2015/11/13/261
> Hello Daniel, > > It's hard to give a straight answer. From my limited perspective (building > a kernel for Sigma boards only) I feel that mmio.c brings nothing. (As you > mentioned, it would be interesting to measure whether having reg_base in > the ctx, rather than as a global is better or worse for perf, though the > actual difference may be lost in the noise.) > > On the other hand, I can see how a different perspective, such as yours, > may see benefits in having all drivers use the same APIs; and there may > be other savings for ARCH_MULTIPLATFORM builds with lots of platforms.
IMO, if all the drivers are using the same code, then optimizing it will benefit to all drivers at the same time.
> I guess if you think it is a good patch, I will defer to your experience.
Ok, I will wait for Russell comments then.
Thanks!
-- Daniel
> I just wish Thomas would take a look at my mmio patch. I will make an > official submission, so that it can be properly shot down :-)
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