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On some Intel CPUs with a P-state but not C-state invariant TSC the TSC

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may also halt in C2 and not just C3 (it seems that in some cases the BIOS
advertises its C3 state as a C2 state in _CST).  Just play it safe and
disable both C2 and C3 states if a user forces the use of the TSC as the
timecounter on such CPUs.

PR:		192316
Differential Revision:	https://reviews.freebsd.org/D1441
No objection from:	jkim
MFC after:	1 week
This commit is contained in:
John Baldwin 2015-01-05 20:44:44 +00:00
parent a9c218da80
commit 92597e064b
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=276724
8 changed files with 36 additions and 23 deletions
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2
sys/amd64/amd64/machdep.c
View File

@ -839,7 +839,7 @@ cpu_idle(int busy)
}
/* Apply AMD APIC timer C1E workaround. */
if (cpu_ident_amdc1e && cpu_disable_deep_sleep) {
if (cpu_ident_amdc1e && cpu_disable_c3_sleep) {
msr = rdmsr(MSR_AMDK8_IPM);
if (msr & AMDK8_CMPHALT)
wrmsr(MSR_AMDK8_IPM, msr & ~AMDK8_CMPHALT);

17
sys/dev/acpica/acpi_cpu.c
View File

@ -85,6 +85,7 @@ struct acpi_cpu_softc {
int cpu_prev_sleep;/* Last idle sleep duration. */
int cpu_features; /* Child driver supported features. */
/* Runtime state. */
int cpu_non_c2; /* Index of lowest non-C2 state. */
int cpu_non_c3; /* Index of lowest non-C3 state. */
u_int cpu_cx_stats[MAX_CX_STATES];/* Cx usage history. */
/* Values for sysctl. */
@ -668,8 +669,10 @@ acpi_cpu_generic_cx_probe(struct acpi_cpu_softc *sc)
cx_ptr->type = ACPI_STATE_C1;
cx_ptr->trans_lat = 0;
cx_ptr++;
sc->cpu_non_c2 = sc->cpu_cx_count;
sc->cpu_non_c3 = sc->cpu_cx_count;
sc->cpu_cx_count++;
cpu_deepest_sleep = 1;
/*
* The spec says P_BLK must be 6 bytes long. However, some systems
@ -695,6 +698,7 @@ acpi_cpu_generic_cx_probe(struct acpi_cpu_softc *sc)
cx_ptr++;
sc->cpu_non_c3 = sc->cpu_cx_count;
sc->cpu_cx_count++;
cpu_deepest_sleep = 2;
}
}
if (sc->cpu_p_blk_len < 6)
@ -711,7 +715,7 @@ acpi_cpu_generic_cx_probe(struct acpi_cpu_softc *sc)
cx_ptr->trans_lat = AcpiGbl_FADT.C3Latency;
cx_ptr++;
sc->cpu_cx_count++;
cpu_can_deep_sleep = 1;
cpu_deepest_sleep = 3;
}
}
}
@ -757,6 +761,7 @@ acpi_cpu_cx_cst(struct acpi_cpu_softc *sc)
count = MAX_CX_STATES;
}
sc->cpu_non_c2 = 0;
sc->cpu_non_c3 = 0;
sc->cpu_cx_count = 0;
cx_ptr = sc->cpu_cx_states;
@ -768,6 +773,7 @@ acpi_cpu_cx_cst(struct acpi_cpu_softc *sc)
cx_ptr->type = ACPI_STATE_C0;
cx_ptr++;
sc->cpu_cx_count++;
cpu_deepest_sleep = 1;
/* Set up all valid states. */
for (i = 0; i < count; i++) {
@ -788,6 +794,7 @@ acpi_cpu_cx_cst(struct acpi_cpu_softc *sc)
/* This is the first C1 state. Use the reserved slot. */
sc->cpu_cx_states[0] = *cx_ptr;
} else {
sc->cpu_non_c2 = sc->cpu_cx_count;
sc->cpu_non_c3 = sc->cpu_cx_count;
cx_ptr++;
sc->cpu_cx_count++;
@ -795,6 +802,8 @@ acpi_cpu_cx_cst(struct acpi_cpu_softc *sc)
continue;
case ACPI_STATE_C2:
sc->cpu_non_c3 = sc->cpu_cx_count;
if (cpu_deepest_sleep < 2)
cpu_deepest_sleep = 2;
break;
case ACPI_STATE_C3:
default:
@ -804,7 +813,7 @@ acpi_cpu_cx_cst(struct acpi_cpu_softc *sc)
device_get_unit(sc->cpu_dev), i));
continue;
} else
cpu_can_deep_sleep = 1;
cpu_deepest_sleep = 3;
break;
}
@ -993,7 +1002,9 @@ acpi_cpu_idle(sbintime_t sbt)
if (sbt >= 0 && us > (sbt >> 12))
us = (sbt >> 12);
cx_next_idx = 0;
if (cpu_disable_deep_sleep)
if (cpu_disable_c2_sleep)
i = min(sc->cpu_cx_lowest, sc->cpu_non_c2);
else if (cpu_disable_c3_sleep)
i = min(sc->cpu_cx_lowest, sc->cpu_non_c3);
else
i = sc->cpu_cx_lowest;

2
sys/i386/i386/machdep.c
View File

@ -1480,7 +1480,7 @@ cpu_idle(int busy)
#ifndef XEN
/* Apply AMD APIC timer C1E workaround. */
if (cpu_ident_amdc1e && cpu_disable_deep_sleep) {
if (cpu_ident_amdc1e && cpu_disable_c3_sleep) {
msr = rdmsr(MSR_AMDK8_IPM);
if (msr & AMDK8_CMPHALT)
wrmsr(MSR_AMDK8_IPM, msr & ~AMDK8_CMPHALT);

11
sys/kern/kern_clocksource.c
View File

@ -54,8 +54,9 @@ __FBSDID("$FreeBSD$");
#include <machine/cpu.h>
#include <machine/smp.h>
int cpu_can_deep_sleep = 0; /* C3 state is available. */
int cpu_disable_deep_sleep = 0; /* Timer dies in C3. */
int cpu_deepest_sleep = 0; /* Deepest Cx state available. */
int cpu_disable_c2_sleep = 0; /* Timer dies in C2. */
int cpu_disable_c3_sleep = 0; /* Timer dies in C3. */
static void setuptimer(void);
static void loadtimer(sbintime_t now, int first);
@ -605,7 +606,7 @@ cpu_initclocks_bsp(void)
else if (!periodic && (timer->et_flags & ET_FLAGS_ONESHOT) == 0)
periodic = 1;
if (timer->et_flags & ET_FLAGS_C3STOP)
cpu_disable_deep_sleep++;
cpu_disable_c3_sleep++;
/*
* We honor the requested 'hz' value.
@ -871,9 +872,9 @@ sysctl_kern_eventtimer_timer(SYSCTL_HANDLER_ARGS)
configtimer(0);
et_free(timer);
if (et->et_flags & ET_FLAGS_C3STOP)
cpu_disable_deep_sleep++;
cpu_disable_c3_sleep++;
if (timer->et_flags & ET_FLAGS_C3STOP)
cpu_disable_deep_sleep--;
cpu_disable_c3_sleep--;
periodic = want_periodic;
timer = et;
et_init(timer, timercb, NULL, NULL);

8
sys/kern/kern_tc.c
View File

@ -1330,10 +1330,10 @@ tc_windup(void)
/* Now is a good time to change timecounters. */
if (th->th_counter != timecounter) {
#ifndef __arm__
if ((timecounter->tc_flags & TC_FLAGS_C3STOP) != 0)
cpu_disable_deep_sleep++;
if ((th->th_counter->tc_flags & TC_FLAGS_C3STOP) != 0)
cpu_disable_deep_sleep--;
if ((timecounter->tc_flags & TC_FLAGS_C2STOP) != 0)
cpu_disable_c2_sleep++;
if ((th->th_counter->tc_flags & TC_FLAGS_C2STOP) != 0)
cpu_disable_c2_sleep--;
#endif
th->th_counter = timecounter;
th->th_offset_count = ncount;

5
sys/sys/systm.h
View File

@ -296,8 +296,9 @@ sbintime_t cpu_idleclock(void);
void cpu_activeclock(void);
void cpu_new_callout(int cpu, sbintime_t bt, sbintime_t bt_opt);
void cpu_et_frequency(struct eventtimer *et, uint64_t newfreq);
extern int cpu_can_deep_sleep;
extern int cpu_disable_deep_sleep;
extern int cpu_deepest_sleep;
extern int cpu_disable_c2_sleep;
extern int cpu_disable_c3_sleep;
int cr_cansee(struct ucred *u1, struct ucred *u2);
int cr_canseesocket(struct ucred *cred, struct socket *so);

2
sys/sys/timetc.h
View File

@ -58,7 +58,7 @@ struct timecounter {
* means "only use at explicit request".
*/
u_int tc_flags;
#define TC_FLAGS_C3STOP 1 /* Timer dies in C3. */
#define TC_FLAGS_C2STOP 1 /* Timer dies in C2+. */
#define TC_FLAGS_SUSPEND_SAFE 2 /*
* Timer functional across
* suspend/resume.

12
sys/x86/x86/tsc.c
View File

@ -522,16 +522,16 @@ init_TSC_tc(void)
}
/*
* 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.
* We cannot use the TSC if it stops incrementing while idle.
* Intel CPUs without a C-state invariant TSC can stop the TSC
* in either C2 or C3.
*/
if (cpu_can_deep_sleep && cpu_vendor_id == CPU_VENDOR_INTEL &&
if (cpu_deepest_sleep >= 2 && cpu_vendor_id == CPU_VENDOR_INTEL &&
(amd_pminfo & AMDPM_TSC_INVARIANT) == 0) {
tsc_timecounter.tc_quality = -1000;
tsc_timecounter.tc_flags |= TC_FLAGS_C3STOP;
tsc_timecounter.tc_flags |= TC_FLAGS_C2STOP;
if (bootverbose)
printf("TSC timecounter disabled: C3 enabled.\n");
printf("TSC timecounter disabled: C2/C3 may halt it.\n");
goto init;
}