Messages in this thread | | | Subject | Re: [PATCH v4 8/8] arm,arm64,drivers: add a prefix to drivers arch_topology interfaces | From | Dietmar Eggemann <> | Date | Mon, 29 May 2017 11:20:24 +0200 |
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Hi Greg,
On 05/26/2017 08:36 PM, Greg KH wrote: > On Fri, May 26, 2017 at 11:10:32AM +0100, Juri Lelli wrote: >> Hi, >> >> On 25/05/17 15:18, Greg KH wrote: >>> On Thu, Apr 20, 2017 at 03:43:16PM +0100, Juri Lelli wrote:
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>>> But this is all really topology stuff, right? Why use "capacity" at >>> all: >>> topology_normalize_cpu() >>> topology_parse_cpu() >>> topology_scale_cpu() >>> topology_set_scale() >>> ? >>> >>> It's always best to put the "subsystem" name first, we have a bad >>> history of getting this wrong in the past by putting the verb first, not >>> the noun. >>> >> >> topology_ works for me. However, I'd keep "capacity" in the names, as we >> might need to topology_normalize_cpu_somethingelse() (etc.) in the >> future? > > Worry about the future, in the future. Change the names then, _IF_ it > becomes an issue. Try to be short and simple please. > >> Updated patch follows. I kept Catalin and Russell's acks as I only >> renamed the functions, please shout if that's not OK. >> >> Greg, if you are fine with this approach, do you still want a complete >> v5 of the set or can you pick this up? > > Am I the one who is supposed to take all of these arm-specific patches? > If so, that's fine, but I need to have acks from the arm maintainers... > > Oh, and drop "capacity" please :)
Once we have driver/base/arch_topology.c in, we want to enable (cpu micro-architectural + max frequency (OPPmax)) invariant and frequency (OPPmin..OPPmax) invariant load-tracking/accounting in the task scheduler for arm and arm64.
The way to do this is to define the task scheduler interfaces arch_scale_cpu_capacity() and arch_scale_freq_capacity() in arch specific code:
#define arch_scale_cpu_capacity topology_scale_cpu_capacity #define arch_scale_freq_capacity topology_scale_freq_capacity
In case an arch is not defining them, the default definitions in kernel/sched/sched.h are used.
So topology_scale_cpu() wouldn't be correct since we scale the _capacity_ by the micro-architectural differences (hence cpu) and not the cpu.
Likewise we will have a function topology_scale_freq_capacity indicating that we scale the capacity by the frequency.
Or would you prefer something like topology_scale_capacity_by_cpu() and topology_scale_capacity_by_freq()?
-- Dietmar
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