[RFC] Event timers on PowerPC

[Andreas Toler]

On 05.09.10 17:46, Alexander Motin wrote:
> Hi.
>
> I have refactored PowerPC event timers code to use new event timers
> infrastructure. I have successfully tested it on PowerMac G4 and
> compiled for MPC85XX.
>
> Patch for HEAD can be found here:
> http://people.freebsd.org/~mav/timers_powerpc.patch
>
> With few additional lines:
> http://people.freebsd.org/~mav/timers_powerpc2.patch
> this patch successfully utilizes dynamic ticks mode of my latest
> one-shot timers patch:
> http://people.freebsd.org/~mav/timers_oneshot8.patch
> , generating only about 50 interrupts per second in idle. With my old
> Motorola PowerPC 7400 CPU I haven't noticed any thermal difference,
> though it would be interesting to try it on faster/consumptive CPUs.
>
> Comments and reviews welcome.

I built and booted the kernel on my G5 SMP.

Below the figures before and after the patch. Both runs were taken after 
a buildkernel.

Do you want me to look for some specific figures?

Andreas

G5 before:
----------
[andreast at bohrium] /usr/src/> vmstat -i
interrupt                          total       rate
irq42: iichb0                       1963          0
irq312: htpic0                      1964          0
irq316: aoagpio0                       1          0
irq282: iichb1                        30          0
irq257: pcm0                           1          0
irq283: ohci0                          1          0
irq284: ohci1                          1          0
irq319: ohci2 ohci+                 5597          0
irq295: ata0                          39          0
irq296: fwohci0                        1          0
irq297: gem0                     1148434        156
irq256: atapci0                    65198          8
irq376: IPI                       669014         91
Total                            1892244        257

G5 after:
---------
[bohrium:~] andreast% vmstat -i
interrupt                          total       rate
cpu0:decrementer                 1957106        783
irq42: iichb0                        994          0
irq312: htpic0                       995          0
irq316: aoagpio0                       1          0
irq282: iichb1                        30          0
irq257: pcm0                           1          0
irq283: ohci0                          1          0
irq284: ohci1                          1          0
irq319: ohci2 ohci+                 1980          0
irq295: ata0                          39          0
irq296: fwohci0                        1          0
irq297: gem0                     1115680        446
irq256: atapci0                    55529         22
irq376: IPI                       445211        178
cpu1:decrementer               176153140      70517
Total                          179730709      71949