If the kernel doesn't report it, it's not enabled. You should try to get an
L2CR entry in your kernel config to enable the G4s L2 cache, or try Tim
Kelly's boot loader that enables the caches before loading the kernel.

I don't think any CPU is going to do very well with only L1 cache and a slow
data bus(50 MHz?)

http://mail-index.netbsd.org/port-macppc/2001/01/05/0007.html


Quoting Riccardo Mottola <rollei@tiscalinet.it>:

> Hey all!
>
> my 9500 go an upgrade bump. That is a G4 card... Of course the
> engineering curiosity was to benchmark "before and after". ANd I used my
> typical matmul and fft benchmarks, I just made then a bit bigger so they
> run longer.
> The result? the 604e 200Mhz is damn fast :)
>
> NetBSD reports the g4 to run at 400Mhz, macos 8.6 reports an unkown
> processor at 450Mhz and I alm almost sure the card is a 450 or a 500mhz.
> (got it used, so no box, sorry). It should have a 1Mb cache but netbsd
> doesn't report it. Maybe it is correct for backside caches? (the 604ev
> card does the same in the 9600)
>
> cpu0 at mainbus0: 7400 (Revision 2.7), ID 0 (primary)
> cpu0: HID0 8294c0a4<EMCP,ECLK,DOZE,DPM,EIEC,ICE,DCE,SGE,BTIC,BHT>
> cpu0: 409.10 MHz
>
>
> here are my results.
> I compiled -O2, -O3 and -O2 with the cpu model (-mcpu=604 or 7400). then
> I did also -O2 -mcpu=7400 -m-no-altivec (and -maltivec) just to go on
> the safe side.
>
> benchmarks
>
> NetBSD 2, gcc 3.3.3
>
> ppc 604e, 200Mhz, 512K cache on board
>
> matmul-double
> -O2            2.38
> -O3            2.42
> -O2 -mcpu=604  2.33
>
> matmul-float
> -O2            2.01
> -O3            2.14
> -O2 -mcpu=604  1.59
>
> fft
> -O2            0.10.89
> -O3            0.10.69
> -O2 -mcpu=604  0.7.55
>
>
> ppc 7400, 410Mhz (?),
>
> matmul-double
> -O2            2.41
> -O3            2.50
> -O2 -mcpu=7400 2.35
> same (no-alti) 3.01
> (altivec)      2.38
>
> matmul-float
> -O2            0.29.89
> -O3            0.30.18
> -O2 -mcpu=7400 0.27.95
> same (no-alti) 0.28.99
> (altivec)      0.30.11
>
> fft
> -O2            0.5.99
> -O3            0.6.05
> -O2 -mcpu=7400 0.6.85
> same (no-alti) 0.6.23
> (altivec)      0.6.17
>
> not exacly exciting, right?
> matmul have in memroy 3 matrix of 160x160 elements thus they should fit
> at least in the 1Mbyte cache. also in the 5125 K cache on-board for the
> slower cpu. FFT should fit in an L2 cache too.
> FFT uses double registers.
>
> I gather that the G4 sucks at double, being only marginally faster than
> the 604e which is clocked at half the cpu speed. float speed is indeed
> faster. Altivec doesn't seem to affect my tests.
>
> Can there be netbsd problems? netbsd related settings that affect cpu
> performance? clockspeed? I have absolutely no experience wih cpu
> upgrades and this is my one and only G4 :)
>
> -R
>
> !DSPAM:42bc116b263506170811304!
>