Re: [PATCH 00/16] timers/hrtimers: Minor cleanups: Part II

From: Viresh Kumar
Date: Tue Apr 01 2014 - 03:03:00 EST


On 1 April 2014 12:03, Viresh Kumar <viresh.kumar@xxxxxxxxxx> wrote:
> So here is the patch by patch analysis (With x86_64_defconfig):
>
> Initial details:
> text data bss dec hex filename
> 7989 408 0 8397 20cd ../bx86/kernel/hrtimer.o
>
>> 73a6cd8 hrtimer: replace 'tab' with 'space' after comma ','
>> 04223a8 hrtimer: Coalesce format fragments in printk()
>> 52fac3f hrtimer: call hrtimer_set_expires_range() from hrtimer_set_expires_range_ns()
>> 535a552 hrtimer: use base->index instead of basenum in switch_hrtimer_base()
> 7989 408 0 8397 20cd ../bx86/kernel/hrtimer.o
>
>> f3a2cdd hrtimer: no need to rewrite '1' to hrtimer_hres_enabled
> 7974 408 0 8382 20be ../bx86/kernel/hrtimer.o
>
> This one actually made a smaller :)
>
>> 479d66f hrtimer: don't rewrite same value to expires_next in hrtimer_force_reprogram()
> 7990 408 0 8398 20ce ../bx86/kernel/hrtimer.o
>> 0e134df hrtimer: use base->hres_active directly instead of hrtimer_hres_active()
> 8006 408 0 8414 20de ../bx86/kernel/hrtimer.o
>
> So, reading from a per-cpu variable is efficient as compared to
> base->hres_active. In that case this patch can be dropped :)

Its a bit awkward now. When I keep this patch at this location
it exactly generates above numbers, i.e. 7990 -> 8006.

But if I revert this patch over top of all 30 commits I have, it
doesn't make a difference. Even applying it again over the
revert doesn't make a difference.

There are no other changes to the concerned routine,
retrigger_next_event() in my commits..
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