Date: Tue, 21 Jun 2011 17:04:01 -0400 From: Jung-uk Kim <jkim@FreeBSD.org> To: freebsd-current@FreeBSD.org Cc: Ian FREISLICH <ianf@clue.co.za> Subject: Re: Time keeping Issues with the low-resolution TSC timecounter Message-ID: <201106211704.04285.jkim@FreeBSD.org> In-Reply-To: <201106211653.34894.jkim@FreeBSD.org> References: <201106171323.43864.jkim@FreeBSD.org> <201106171455.00088.jkim@FreeBSD.org> <201106211653.34894.jkim@FreeBSD.org>
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On Tuesday 21 June 2011 04:53 pm, Jung-uk Kim wrote:
> Can you please try the attached patch? It should disable
> TSC/TSC-low timecounter for your CPU models, I think.
Sorry, I attached a wrong patch. Please ignore the previous one and
try this, instead.
Jung-uk Kim
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Index: sys/dev/acpica/acpi_cpu.c
===================================================================
--- sys/dev/acpica/acpi_cpu.c (revision 223372)
+++ sys/dev/acpica/acpi_cpu.c (working copy)
@@ -856,6 +856,8 @@ acpi_cpu_cx_list(struct acpi_cpu_softc *sc)
sbuf_printf(&sb, "C%d/%d ", i + 1, sc->cpu_cx_states[i].trans_lat);
if (sc->cpu_cx_states[i].type < ACPI_STATE_C3)
sc->cpu_non_c3 = i;
+ else
+ cpu_can_deep_sleep = 1;
}
sbuf_trim(&sb);
sbuf_finish(&sb);
Index: sys/kern/kern_clocksource.c
===================================================================
--- sys/kern/kern_clocksource.c (revision 223372)
+++ sys/kern/kern_clocksource.c (working copy)
@@ -59,6 +59,7 @@ __FBSDID("$FreeBSD$");
cyclic_clock_func_t cyclic_clock_func = NULL;
#endif
+int cpu_can_deep_sleep = 0; /* C3 state is available. */
int cpu_disable_deep_sleep = 0; /* Timer dies in C3. */
static void setuptimer(void);
Index: sys/sys/systm.h
===================================================================
--- sys/sys/systm.h (revision 223372)
+++ sys/sys/systm.h (working copy)
@@ -253,6 +253,7 @@ void cpu_startprofclock(void);
void cpu_stopprofclock(void);
void cpu_idleclock(void);
void cpu_activeclock(void);
+extern int cpu_can_deep_sleep;
extern int cpu_disable_deep_sleep;
int cr_cansee(struct ucred *u1, struct ucred *u2);
Index: sys/x86/x86/tsc.c
===================================================================
--- sys/x86/x86/tsc.c (revision 223372)
+++ sys/x86/x86/tsc.c (working copy)
@@ -444,6 +444,19 @@ init_TSC_tc(void)
goto init;
}
+ /*
+ * We cannot use the TSC if it stops incrementing in deep sleep.
+ * Currently only Intel CPUs are known for this problem unless
+ * the invariant TSC bit is set.
+ */
+ if (cpu_can_deep_sleep && cpu_vendor_id == CPU_VENDOR_INTEL &&
+ (amd_pminfo & AMDPM_TSC_INVARIANT) == 0) {
+ tsc_timecounter.tc_quality = -1000;
+ if (bootverbose)
+ printf("TSC timecounter disabled: C3 enabled.\n");
+ goto init;
+ }
+
#ifdef SMP
/*
* We can not use the TSC in SMP mode unless the TSCs on all CPUs are
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