powerpc: Show current speed in /proc/cpuinfo

On other architectures, the frequency in /proc/cpuinfo moves with cpufreq changes. It makes sense to do the same on powerpc to keep users from getting confused. Fall back to old ppc_proc_freq for non-cpufreq systems.

Also change the format to three decimals, having full Hz granularity is silly these days.

Signed-off-by Olof Johansson <[email protected]>

Index: powerpc/arch/powerpc/kernel/setup-common.c
===================================================================

arch/powerpc/kernel/setup-common.c +2 -0

@@ -29,6 +29,7 @@
 #include <linux/root_dev.h>
 #include <linux/notifier.h>
 #include <linux/cpu.h>
+#include <linux/cpufreq.h>
 #include <linux/unistd.h>
 #include <linux/serial.h>
 #include <linux/serial_8250.h>

@@ -160,6 +161,7 @@ static int show_cpuinfo(struct seq_file 
 	unsigned int pvr;
 	unsigned short maj;
 	unsigned short min;
+	unsigned int freq;
 
 	if (cpu_id == NR_CPUS) {
 #if defined(CONFIG_SMP) && defined(CONFIG_PPC32)

arch/powerpc/kernel/setup-common.c +7 -0

+
+	if (!freq)
+		/* ppc_proc_freq is in Hz */
+		freq = ppc_proc_freq / 1000;
+
+	if (freq)
+		seq_printf(m, "clock\t\t: %u.%03uMHz\n", freq / 1000, freq % 1000);

Would it not be relevant to keep listing the maximum CPU speed as well as the real, current CPU speed?

Would it not be relevant to keep listing the maximum CPU speed as well as the real, current CPU speed?

Intel encode this into their CPUID string and when I bring up Windows' System Properties dialog I get this;

Intel(R) Pentium(R) M processor 1.70GHz
593MHz, 512MB of RAM

So you can always, always find out very easily what spec your processor is, and not just what cpufreq has done with it?

arch/powerpc/kernel/setup-common.c static int show_cpuinfo(struct seq_file · line 232

Quoted 2 lines

arch/powerpc/kernel/setup-common.c +2 -0

+	/* cpufreq_speed_get() is in kHz */
+	freq = cpufreq_quick_get(cpu_id);

Is it speed or quick? This and the comment below confused me, KHz or Hz? :D

On other architectures, the frequency in /proc/cpuinfo moves with cpufreq changes. It makes sense to do the same on powerpc to keep users from getting confused. Fall back to old ppc_proc_freq for non-cpufreq systems.

Also change the format to three decimals, having full Hz granularity is silly these days.

Quoted 4 lines · Olof Johansson

On other architectures, the frequency in /proc/cpuinfo moves with cpufreq changes. It makes sense to do the same on powerpc to keep users from getting confused. Fall back to old ppc_proc_freq for non-cpufreq systems.

Quoted 2 lines

Also change the format to three decimals, having full Hz granularity is silly these days.

That doesn't work if cpufreq is a module... on mac, I used to have exactly that hack, though at one point I changed to just updating ppc_proc_freq :-) But then, it's easy because I only change the freq on all CPUs at the same time. Might be different for you.

On other architectures, the frequency in /proc/cpuinfo moves with cpufreq changes. It makes sense to do the same on powerpc to keep users from getting confused.
=20
Change the format to three decimals, having full Hz granularity is silly these days. Also specify in output if it's cpufreq or firmware-reported:
=20
clock =A0 =A0 =A0 =A0 =A0 : 1250.000MHz (from firmware)
or:
clock =A0 =A0 =A0 =A0 =A0 : 2500.000MHz (actual speed)

Quoted 10 lines · Olof Johansson

On other architectures, the frequency in /proc/cpuinfo moves with cpufreq changes. It makes sense to do the same on powerpc to keep users from getting confused.

Change the format to three decimals, having full Hz granularity is silly these days. Also specify in output if it's cpufreq or firmware-reported:

clock ? ? ? ? ? : 1250.000MHz (from firmware)
or:
clock ? ? ? ? ? : 2500.000MHz (actual speed)

Good idea, but I'd be _very_ careful with changing any field in /proc/cpuinfo. Having the extra text in there can easily confuse parsers in poorly written user applications, maybe even in good ones ;-)

How about rather adding a new line in there for one of the fields, either

arch/powerpc/kernel/setup-common.c static int show_cpuinfo(struct seq_file · line 231

Quoted 2 lines · On Thu, 3 May 2007 22:16:12 -0500 [email protected] (Olof Johansson) wrote:

arch/powerpc/kernel/setup-common.c +1 -0

+	/* ppc_proc_freq is in MHz */

                               ^^^

Actually Hz :-)

On other architectures, the frequency in /proc/cpuinfo moves with cpufreq changes. It makes sense to do the same on powerpc to keep users from getting confused.

Quoted 3 lines · Olof Johansson

On other architectures, the frequency in /proc/cpuinfo moves with cpufreq changes. It makes sense to do the same on powerpc to keep users from getting confused.

Well, it does on powermac already, because ppc_proc_freq gets adjusted... So at the very least, your patch description needs to be changed.

Do you have a situation where the CPUs in a system can have different clock frequencies? If not, why not just set ppc_proc_freq when the frequency changes?