On Wed, Aug 17, 2022 at 09:00:12PM +1000, Jonathan Gray wrote:
> On Wed, Aug 17, 2022 at 04:53:20PM +1000, Jonathan Gray wrote:
> >
> > It seems to me it would be cleaner if the decision of what to use for
> > delay could be moved into an md file.
> >
> > Or abstract it by having a numeric weight like timecounters or driver
> > match return numbers.
>
> diff against your previous, does not change lapic_delay
Sorry for the delay.
:)
I was out of town.
I slept on this and you're right, this is better.
Couple tweaks:
- Move the quality numbers into cpu.h and give them names. That way,
the next time Intel, or AMD, or Microsoft or [...] does something
foolish we don't need to rototill all these files to juggle the
quality hierarchy.
- Update both amd64 and i386's lapic.c to use delay_init(). While we
have a lapic_delay() in the tree it should cooperate with everything
else.
- Include <machine/cpu.h> in any files calling delay_init() where it
isn't already included.
- Give the variables in delay_init() real names.
I'm unsure about two small things:
- Can i386 use hv_delay()? The i386 GENERIC config does not list
hyperv(4) support so my guess is "no" and I have excluded
HV_DELAY_QUALITY from i386's cpu.h.
- If a Hyper-V guest could choose between hv_delay() and
lapic_delay(), which would be preferable? Right now I
have hv_delay() scored lower than lapic_delay().
Once we've sorted those out, are you OK with the attached patch?
mlarkin: still ok?
Index: sys/arch/amd64/amd64/lapic.c
===================================================================
RCS file: /cvs/src/sys/arch/amd64/amd64/lapic.c,v
retrieving revision 1.60
diff -u -p -r1.60 lapic.c
--- sys/arch/amd64/amd64/lapic.c 15 Aug 2022 04:17:50 -0000 1.60
+++ sys/arch/amd64/amd64/lapic.c 22 Aug 2022 14:33:30 -0000
@@ -486,8 +486,6 @@ wait_next_cycle(void)
}
}
-extern void tsc_delay(int);
-
/*
* Calibrate the local apic count-down timer (which is running at
* bus-clock speed) vs. the i8254 counter/timer (which is running at
@@ -592,8 +590,7 @@ skip_calibration:
* Now that the timer's calibrated, use the apic timer routines
* for all our timing needs..
*/
- if (delay_func == i8254_delay)
- delay_func = lapic_delay;
+ delay_init(lapic_delay, LAPIC_DELAY_QUALITY);
initclock_func = lapic_initclocks;
}
}
Index: sys/arch/amd64/amd64/machdep.c
===================================================================
RCS file: /cvs/src/sys/arch/amd64/amd64/machdep.c,v
retrieving revision 1.279
diff -u -p -r1.279 machdep.c
--- sys/arch/amd64/amd64/machdep.c 7 Aug 2022 23:56:06 -0000 1.279
+++ sys/arch/amd64/amd64/machdep.c 22 Aug 2022 14:33:30 -0000
@@ -2069,3 +2069,13 @@ check_context(const struct reg *regs, st
return 0;
}
+
+void
+delay_init(void(*fn)(int), int fn_quality)
+{
+ static int cur_quality = 0;
+ if (fn_quality > cur_quality) {
+ delay_func = fn;
+ cur_quality = fn_quality;
+ }
+}
Index: sys/arch/amd64/amd64/tsc.c
===================================================================
RCS file: /cvs/src/sys/arch/amd64/amd64/tsc.c,v
retrieving revision 1.25
diff -u -p -r1.25 tsc.c
--- sys/arch/amd64/amd64/tsc.c 12 Aug 2022 02:20:36 -0000 1.25
+++ sys/arch/amd64/amd64/tsc.c 22 Aug 2022 14:33:30 -0000
@@ -109,7 +109,7 @@ tsc_identify(struct cpu_info *ci)
tsc_frequency = tsc_freq_cpuid(ci);
if (tsc_frequency > 0)
- delay_func = tsc_delay;
+ delay_init(tsc_delay, TSC_DELAY_QUALITY);
}
static inline int
Index: sys/arch/amd64/include/cpu.h
===================================================================
RCS file: /cvs/src/sys/arch/amd64/include/cpu.h,v
retrieving revision 1.148
diff -u -p -r1.148 cpu.h
--- sys/arch/amd64/include/cpu.h 22 Aug 2022 08:57:54 -0000 1.148
+++ sys/arch/amd64/include/cpu.h 22 Aug 2022 14:33:30 -0000
@@ -364,6 +364,13 @@ struct timeval;
#define DELAY(x) (*delay_func)(x)
#define delay(x) (*delay_func)(x)
+void delay_init(void(*)(int), int);
+
+#define ACPITIMER_DELAY_QUALITY 100
+#define ACPIHPET_DELAY_QUALITY 200
+#define HV_DELAY_QUALITY 250
+#define LAPIC_DELAY_QUALITY 300
+#define TSC_DELAY_QUALITY 400
#ifdef _KERNEL
/* locore.S */
Index: sys/arch/i386/i386/lapic.c
===================================================================
RCS file: /cvs/src/sys/arch/i386/i386/lapic.c,v
retrieving revision 1.49
diff -u -p -r1.49 lapic.c
--- sys/arch/i386/i386/lapic.c 15 Aug 2022 04:17:50 -0000 1.49
+++ sys/arch/i386/i386/lapic.c 22 Aug 2022 14:33:30 -0000
@@ -395,7 +395,7 @@ lapic_calibrate_timer(struct cpu_info *c
* Now that the timer's calibrated, use the apic timer routines
* for all our timing needs..
*/
- delay_func = lapic_delay;
+ delay_init(lapic_delay, LAPIC_DELAY_QUALITY);
initclock_func = lapic_initclocks;
}
}
Index: sys/arch/i386/i386/machdep.c
===================================================================
RCS file: /cvs/src/sys/arch/i386/i386/machdep.c,v
retrieving revision 1.654
diff -u -p -r1.654 machdep.c
--- sys/arch/i386/i386/machdep.c 20 Aug 2022 23:33:53 -0000 1.654
+++ sys/arch/i386/i386/machdep.c 22 Aug 2022 14:33:33 -0000
@@ -3988,3 +3988,13 @@ cpu_rnd_messybits(void)
nanotime(&ts);
return (ts.tv_nsec ^ (ts.tv_sec << 20));
}
+
+void
+delay_init(void(*fn)(int), int fn_quality)
+{
+ static int cur_quality = 0;
+ if (fn_quality > cur_quality) {
+ delay_func = fn;
+ cur_quality = fn_quality;
+ }
+}
Index: sys/arch/i386/include/cpu.h
===================================================================
RCS file: /cvs/src/sys/arch/i386/include/cpu.h,v
retrieving revision 1.176
diff -u -p -r1.176 cpu.h
--- sys/arch/i386/include/cpu.h 12 Jul 2022 05:45:49 -0000 1.176
+++ sys/arch/i386/include/cpu.h 22 Aug 2022 14:33:33 -0000
@@ -307,6 +307,12 @@ struct timeval;
#define DELAY(x) (*delay_func)(x)
#define delay(x) (*delay_func)(x)
+void delay_init(void(*)(int), int);
+
+#define ACPITIMER_DELAY_QUALITY 100
+#define ACPIHPET_DELAY_QUALITY 200
+#define LAPIC_DELAY_QUALITY 300
+
/*
* High resolution clock support (Pentium only)
*/
Index: sys/dev/acpi/acpitimer.c
===================================================================
RCS file: /cvs/src/sys/dev/acpi/acpitimer.c,v
retrieving revision 1.15
diff -u -p -r1.15 acpitimer.c
--- sys/dev/acpi/acpitimer.c 6 Apr 2022 18:59:27 -0000 1.15
+++ sys/dev/acpi/acpitimer.c 22 Aug 2022 14:33:33 -0000
@@ -18,17 +18,22 @@
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/device.h>
+#include <sys/stdint.h>
#include <sys/timetc.h>
#include <machine/bus.h>
+#include <machine/cpu.h>
#include <dev/acpi/acpireg.h>
#include <dev/acpi/acpivar.h>
+struct acpitimer_softc;
+
int acpitimermatch(struct device *, void *, void *);
void acpitimerattach(struct device *, struct device *, void *);
-
+void acpitimer_delay(int);
u_int acpi_get_timecount(struct timecounter *tc);
+uint32_t acpitimer_read(struct acpitimer_softc *);
static struct timecounter acpi_timecounter = {
.tc_get_timecount = acpi_get_timecount,
@@ -98,18 +103,43 @@ acpitimerattach(struct device *parent, s
acpi_timecounter.tc_priv = sc;
acpi_timecounter.tc_name = sc->sc_dev.dv_xname;
tc_init(&acpi_timecounter);
+
+ delay_init(acpitimer_delay, ACPITIMER_DELAY_QUALITY);
+
#if defined(__amd64__)
extern void cpu_recalibrate_tsc(struct timecounter *);
cpu_recalibrate_tsc(&acpi_timecounter);
#endif
}
+void
+acpitimer_delay(int usecs)
+{
+ uint64_t count = 0, cycles;
+ struct acpitimer_softc *sc = acpi_timecounter.tc_priv;
+ uint32_t mask = acpi_timecounter.tc_counter_mask;
+ uint32_t val1, val2;
+
+ val2 = acpitimer_read(sc);
+ cycles = usecs * acpi_timecounter.tc_frequency / 1000000;
+ while (count < cycles) {
+ CPU_BUSY_CYCLE();
+ val1 = val2;
+ val2 = acpitimer_read(sc);
+ count += (val2 - val1) & mask;
+ }
+}
u_int
acpi_get_timecount(struct timecounter *tc)
{
- struct acpitimer_softc *sc = tc->tc_priv;
- u_int u1, u2, u3;
+ return acpitimer_read(tc->tc_priv);
+}
+
+uint32_t
+acpitimer_read(struct acpitimer_softc *sc)
+{
+ uint32_t u1, u2, u3;
u2 = bus_space_read_4(sc->sc_iot, sc->sc_ioh, 0);
u3 = bus_space_read_4(sc->sc_iot, sc->sc_ioh, 0);
Index: sys/dev/acpi/acpihpet.c
===================================================================
RCS file: /cvs/src/sys/dev/acpi/acpihpet.c,v
retrieving revision 1.26
diff -u -p -r1.26 acpihpet.c
--- sys/dev/acpi/acpihpet.c 6 Apr 2022 18:59:27 -0000 1.26
+++ sys/dev/acpi/acpihpet.c 22 Aug 2022 14:33:33 -0000
@@ -18,9 +18,11 @@
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/device.h>
+#include <sys/stdint.h>
#include <sys/timetc.h>
#include <machine/bus.h>
+#include <machine/cpu.h>
#include <dev/acpi/acpireg.h>
#include <dev/acpi/acpivar.h>
@@ -31,7 +33,7 @@ int acpihpet_attached;
int acpihpet_match(struct device *, void *, void *);
void acpihpet_attach(struct device *, struct device *, void *);
int acpihpet_activate(struct device *, int);
-
+void acpihpet_delay(int);
u_int acpihpet_gettime(struct timecounter *tc);
uint64_t acpihpet_r(bus_space_tag_t _iot, bus_space_handle_t _ioh,
@@ -262,15 +264,30 @@ acpihpet_attach(struct device *parent, s
freq = 1000000000000000ull / period;
printf(": %lld Hz\n", freq);
- hpet_timecounter.tc_frequency = (uint32_t)freq;
+ hpet_timecounter.tc_frequency = freq;
hpet_timecounter.tc_priv = sc;
hpet_timecounter.tc_name = sc->sc_dev.dv_xname;
tc_init(&hpet_timecounter);
+
+ delay_init(acpihpet_delay, ACPIHPET_DELAY_QUALITY);
+
#if defined(__amd64__)
extern void cpu_recalibrate_tsc(struct timecounter *);
cpu_recalibrate_tsc(&hpet_timecounter);
#endif
acpihpet_attached++;
+}
+
+void
+acpihpet_delay(int usecs)
+{
+ uint64_t c, s;
+ struct acpihpet_softc *sc = hpet_timecounter.tc_priv;
+
+ s = acpihpet_r(sc->sc_iot, sc->sc_ioh, HPET_MAIN_COUNTER);
+ c = usecs * hpet_timecounter.tc_frequency / 1000000;
+ while (acpihpet_r(sc->sc_iot, sc->sc_ioh, HPET_MAIN_COUNTER) - s < c)
+ CPU_BUSY_CYCLE();
}
u_int
Index: sys/dev/pv/pvbus.c
===================================================================
RCS file: /cvs/src/sys/dev/pv/pvbus.c,v
retrieving revision 1.24
diff -u -p -r1.24 pvbus.c
--- sys/dev/pv/pvbus.c 5 Nov 2021 11:38:29 -0000 1.24
+++ sys/dev/pv/pvbus.c 22 Aug 2022 14:33:33 -0000
@@ -319,9 +319,8 @@ pvbus_hyperv(struct pvbus_hv *hv)
HYPERV_VERSION_EBX_MINOR_S;
#if NHYPERV > 0
- if (hv->hv_features & CPUID_HV_MSR_TIME_REFCNT &&
- delay_func == i8254_delay)
- delay_func = hv_delay;
+ if (hv->hv_features & CPUID_HV_MSR_TIME_REFCNT)
+ delay_init(hv_delay, HV_DELAY_QUALITY);
#endif
}
