Re: [lkp] [+64 bytes kernel size regression] [i386-tinyconfig] [78532abaf5] x86/tsc: Add option to force frequency recalibration with HW timer

[Feng Tang <feng.tang@intel.com>]

On Sat, Jan 07, 2023 at 08:01:32AM -0800, Paul E. McKenney wrote:
> On Sat, Jan 07, 2023 at 05:03:05PM +0800, kernel test robot wrote:
> > 
> > FYI, we noticed a +64 bytes kernel size regression due to commit:
> > 
> > commit: 78532abaf5f1c973c99680960ae22bd797951ddf (x86/tsc: Add option to force frequency recalibration with HW timer)
> > https://git.kernel.org/cgit/linux/kernel/git/paulmck/linux-rcu.git workqueue.2023.01.06a
> > 
> > 
> > Details as below (size data is obtained by `nm --size-sort vmlinux`):
> > 
> > 8913f44d: clocksource: Permit limited-duration clocksource watchdogging
> > 78532aba: x86/tsc: Add option to force frequency recalibration with HW timer
> 
> Perhaps there should be a Kconfig option to disable the clocksource
> watchdog?  Not sure that a minimal kernel would worry about such things.

Yes, there is a CONFIG_CLOCKSOURCE_WATCHDOG option. For 78532aba, IMHO,
64 bytes is a relatively small cost comparing to its potential value.

Thanks,
Feng

> 
> 							Thanx, Paul
> 
> > +----------------------------------+----------+----------+-------+
> > |              symbol              | 8913f44d | 78532aba | delta |
> > +----------------------------------+----------+----------+-------+
> > | bzImage                          | 495904   | 495968   | 64    |
> > | nm.t.tsc_setup                   | 103      | 129      | 26    |
> > | nm.t.init_tsc_clocksource        | 111      | 132      | 21    |
> > | nm.t.tsc_refine_calibration_work | 427      | 440      | 13    |
> > | nm.d.tsc_force_recalibrate       | 0        | 4        | 4     |
> > +----------------------------------+----------+----------+-------+
> > 
> > 
> > 
> > Thanks
> >