[email protected] (Robert Elz) writes:
> Date: Thu, 4 Aug 2022 12:49:35 -0000 (UTC)
> From: [email protected] (Michael van Elst)
> Message-ID: <[email protected]>
> | The measurement runs with enabled interrupts. If you have lots of
> interrupts
> | or interrupts that take some time, the measurement is biased.
> |
> | Console output can do this.
>That is what I suspected. A normal boot dmesg on this system is about
>50KB. With PCI_CONFIG_DUMP it is about 1MB (just a bit over). That's
>a lot of work for wscons scrolling (via the BIOS the whole time - the
>dump all happens before the console switches to graphics mode) a fairly
>large screen.
Does this help ?
Index: sys/arch/x86/x86/cpu.c
===================================================================
RCS file: /cvsroot/src/sys/arch/x86/x86/cpu.c,v
retrieving revision 1.203
diff -p -u -r1.203 cpu.c
--- sys/arch/x86/x86/cpu.c 1 Apr 2022 19:57:22 -0000 1.203
+++ sys/arch/x86/x86/cpu.c 7 Aug 2022 09:17:12 -0000
@@ -1336,9 +1336,16 @@ cpu_get_tsc_freq(struct cpu_info *ci)
*/
if (ci->ci_data.cpu_cc_freq == 0)
freq = freq_from_cpuid = cpu_tsc_freq_cpuid(ci);
+ if (freq != 0)
+ aprint_debug_dev(ci->ci_dev, "TSC freq "
+ "from CPUID %" PRIu64 " Hz\n", freq);
#if NHPET > 0
- if (freq == 0)
+ if (freq == 0) {
freq = hpet_tsc_freq();
+ if (freq != 0)
+ aprint_debug_dev(ci->ci_dev, "TSC freq "
+ "from HPET %" PRIu64 " Hz\n", freq);
+ }
#endif
if (freq == 0) {
/*
@@ -1348,20 +1355,33 @@ cpu_get_tsc_freq(struct cpu_info *ci)
*/
overhead = 0;
for (int i = 0; i <= 8; i++) {
+ const int s = splhigh();
t0 = cpu_counter();
delay_func(0);
t1 = cpu_counter();
+ splx(s);
if (i > 0) {
overhead += (t1 - t0);
}
}
overhead >>= 3;
- /* Now do the calibration. */
- t0 = cpu_counter();
- delay_func(100000);
- t1 = cpu_counter();
- freq = (t1 - t0 - overhead) * 10;
+ /*
+ * Now do the calibration.
+ */
+ freq = 0;
+ for (int i = 0; i < 1000; i++) {
+ const int s = splhigh();
+ t0 = cpu_counter();
+ delay_func(100);
+ t1 = cpu_counter();
+ splx(s);
+ freq += t1 - t0 - overhead;
+ }
+ freq = freq * 10;
+
+ aprint_debug_dev(ci->ci_dev, "TSC freq "
+ "from delay %" PRIu64 " Hz\n", freq);
}
if (ci->ci_data.cpu_cc_freq != 0) {
freq_from_cpuid = cpu_tsc_freq_cpuid(ci);
