On Thu, Dec 16, 2021 at 11:49:15AM +0100, Uwe Kleine-König wrote: > hello William, > > On Thu, Dec 16, 2021 at 02:25:03PM +0900, William Breathitt Gray wrote: > > On Mon, Dec 13, 2021 at 12:43:12PM +0100, Uwe Kleine-König wrote: > > > Using counter->priv is a memory read and so more expensive than > > > container_of which is only an addition. (In this case even a noop > > > because the offset is 0.) > > > > > > So container_of is expected to be a tad faster, it's type-safe, and > > > produces smaller code (ARCH=arm allmodconfig): > > > > > > $ source/scripts/bloat-o-meter drivers/counter/ti-eqep.o-pre drivers/counter/ti-eqep.o > > > add/remove: 0/0 grow/shrink: 0/9 up/down: 0/-108 (-108) > > > Function old new delta > > > ti_eqep_position_enable_write 132 120 -12 > > > ti_eqep_position_enable_read 260 248 -12 > > > ti_eqep_position_ceiling_write 132 120 -12 > > > ti_eqep_position_ceiling_read 236 224 -12 > > > ti_eqep_function_write 220 208 -12 > > > ti_eqep_function_read 372 360 -12 > > > ti_eqep_count_write 312 300 -12 > > > ti_eqep_count_read 236 224 -12 > > > ti_eqep_action_read 664 652 -12 > > > Total: Before=4598, After=4490, chg -2.35% > > > > > > Signed-off-by: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx> > > > > I'll pick this up and submit it with the rest of the Counter changes for > > this cycle. > > This is great. The same transformation could be done for the other > drivers using the priv pointer. Then priv could be removed from struct > counter_device. Good idea? Sure, that sounds reasonable. Create a patchset with the changes, CC the respective driver maintainers, and we'll see if we can merge those too. William Breathitt Gray > > A quick prototype patch yields: > > drivers/counter/104-quad-8.o > add/remove: 0/0 grow/shrink: 5/17 up/down: 76/-172 (-96) > Total: Before=11802, After=11706, chg -0.81% > drivers/counter/ftm-quaddec.o > add/remove: 0/0 grow/shrink: 0/5 up/down: 0/-60 (-60) > Total: Before=5096, After=5036, chg -1.18% > drivers/counter/intel-qep.o > add/remove: 0/0 grow/shrink: 0/10 up/down: 0/-116 (-116) > Total: Before=4867, After=4751, chg -2.38% > drivers/counter/interrupt-cnt.o > add/remove: 0/0 grow/shrink: 0/6 up/down: 0/-60 (-60) > Total: Before=2841, After=2781, chg -2.11% > drivers/counter/microchip-tcb-capture.o > add/remove: 0/0 grow/shrink: 1/6 up/down: 12/-68 (-56) > Total: Before=5920, After=5864, chg -0.95% > drivers/counter/stm32-lptimer-cnt.o > add/remove: 0/0 grow/shrink: 0/10 up/down: 0/-140 (-140) > Total: Before=6458, After=6318, chg -2.17% > drivers/counter/stm32-timer-cnt.o > add/remove: 0/0 grow/shrink: 0/11 up/down: 0/-132 (-132) > Total: Before=5504, After=5372, chg -2.40% > drivers/counter/ti-eqep.o > add/remove: 0/0 grow/shrink: 0/10 up/down: 0/-120 (-120) > Total: Before=4598, After=4478, chg -2.61% > > (the ti-eqep object file got a bit smaller, probably because I removed > the priv member from struct counter_device.) > > Best regards > Uwe > > -- > Pengutronix e.K. | Uwe Kleine-König | > Industrial Linux Solutions | https://www.pengutronix.de/ |
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