CPU frequency scaling doesn't work on Mac mini G4

classic Classic list List threaded Threaded
1 message Options
Reply | Threaded
Open this post in threaded view
|

CPU frequency scaling doesn't work on Mac mini G4

freebsd-ppc mailing list
Hi,

I've just noticed a strange behavior regarding frequency scaling on the
Mac mini G4. When I tried to set the CPU frequency using powerd, it
(and "sysctl dev.cpu.0.freq") reports that the frequency has been
changed, yet a test using "openssl speed" shows similar performance
between the two frequencies.

Here's the result of running "openssl speed -evp chacha20" with
"powerd -n maximum" (1416 MHz):

type 16 bytes 64 bytes 256 bytes 1024 bytes 8192 bytes 16384 bytes
chacha20 40326.69k 61947.78k 70339.29k 72921.32k 73479.72k 73307.48k

And with "powerd -n minimum" (708 MHz):

type 16 bytes 64 bytes 256 bytes 1024 bytes 8192 bytes 16384 bytes
chacha20 40314.57k 62121.26k 70303.44k 72740.17k 73468.76k 73520.78k

I expect that openssl would run slower when the CPU frequency is set
to minimum, but that's not the case here. Is it a bug or did I use
the wrong program to measure it?

The system is a freshly-installed 12.0-RELEASE on the 1.4 GHz model.

_______________________________________________
[hidden email] mailing list
https://lists.freebsd.org/mailman/listinfo/freebsd-ppc
To unsubscribe, send any mail to "[hidden email]"