Don't rely on CPU cycles to measure time.

We have a proper clocksource in the kernel, use this instead.

This commit also fixes jackd on ARM boards with newer Linux kernels
where /proc/cpuinfo has changed.

config/os/gnu-linux/time.c

@@ -23,7 +23,6 @@
 
 #include <stdint.h>
 
-static jack_time_t __jack_cpu_mhz = 0;
 jack_time_t (*_jack_get_microseconds)(void) = 0;
 
 #if defined(__gnu_linux__) && (defined(__i386__) || defined(__x86_64__))
@@ -113,68 +112,10 @@ jack_get_microseconds_from_hpet (void)
 #endif /* HPET_SUPPORT */
 
 
-jack_time_t 
-jack_get_microseconds_from_cycles (void) {
-	return get_cycles() / __jack_cpu_mhz;
-}
-
-/*
- * This is another kludge.  It looks CPU-dependent, but actually it
- * reflects the lack of standards for the Linux kernel formatting of
- * /proc/cpuinfo.
- */
-
-jack_time_t
-jack_get_mhz (void)
-{
-	FILE *f = fopen("/proc/cpuinfo", "r");
-	if (f == 0)
-	{
-		perror("can't open /proc/cpuinfo\n");
-		exit(1);
-	}
-
-	for ( ; ; )
-	{
-		jack_time_t mhz;
-		int ret;
-		char buf[1000];
-
-		if (fgets(buf, sizeof(buf), f) == NULL) {
-			jack_error ("FATAL: cannot locate cpu MHz in "
-				    "/proc/cpuinfo\n");
-			exit(1);
-		}
-
-#if defined(__powerpc__)
-		ret = sscanf(buf, "clock\t: %" SCNu64 "MHz", &mhz);
-#elif defined( __i386__ ) || defined (__hppa__)  || defined (__ia64__) || \
-      defined(__x86_64__)
-		ret = sscanf(buf, "cpu MHz         : %" SCNu64, &mhz);
-#elif defined( __sparc__ )
-		ret = sscanf(buf, "Cpu0Bogo        : %" SCNu64, &mhz);
-#elif defined( __mc68000__ )
-		ret = sscanf(buf, "Clocking:       %" SCNu64, &mhz);
-#elif defined( __s390__  )
-		ret = sscanf(buf, "bogomips per cpu: %" SCNu64, &mhz);
-#elif defined( __sh__  )
-		ret = sscanf(buf, "bogomips        : %" SCNu64, &mhz);
-#else /* MIPS, ARM, alpha */
-		ret = sscanf(buf, "BogoMIPS        : %" SCNu64, &mhz);
-#endif 
-
-		if (ret == 1)
-		{
-			fclose(f);
-			return (jack_time_t)mhz;
-		}
-	}
-}
-
 void
 jack_init_time ()
 {
-	__jack_cpu_mhz = jack_get_mhz ();
+	/* nothing to do on a generic system - we use the system clock */
 }
 
 void
@@ -182,10 +123,6 @@ jack_set_clock_source (jack_timer_type_t clocksrc)
 {
 	switch (clocksrc)
 	{
-	case JACK_TIMER_CYCLE_COUNTER:
-		_jack_get_microseconds = jack_get_microseconds_from_cycles;
-		break;
-
 	case JACK_TIMER_HPET:
 		if (jack_hpet_init () == 0) {
 			_jack_get_microseconds = jack_get_microseconds_from_hpet;