IA-PC HPET IA-PC HPET (High Precision Event Timer) is a specification which was jointly developed by Intel and Microsoft in the early part of this decade.. (High Precision Event Classes) er en spesifikasjon som ble utviklet i fellesskap av Intel og Microsoft i første del av dette tiåret .. The latest version is dated October 2004. Den nyeste versjonen er datert oktober 2004. It's stated purpose is to Det er uttalt formål er å
initially supplement and eventually replace the legacy 8254 Programmable Interval Timer and the Real Time Clock Periodic Interrupt generation functions that are currently used as the 'de-facto' timer hardware for IA-PCs. først supplere og erstatte arven 8254 programmerbare intervalltidtaker og Real Time Clock Periodiske Interrupt generasjon funksjoner som i dag brukes som «de-facto" timer hardware for IA-PCer.
The Det HPET HPET architecture defines a set of timers that can be used by the operating system. arkitekturen definerer et sett med tidtakere som kan brukes av operativsystemet. A timer block is a combination of a single counter and up to 32 comparators and match registers. En timer blokk er en kombinasjon av en enkelt teller og opp til 32 Comparators og match registre. The comparator compares the contents of the match register against the value of a free running monotonic up-counter. Det komparator sammenligner innholdet av kampen registeret mot verdien av en gratis kjøre monotonic up-counter. When the output of the up-counter equals the value in the match register an interrupt is generated. Når produksjonen av den opp-telleren er lik verdien i kampen registeret et avbrudd er generert. Each of the comparators can output an interrupt. Hvert av de Comparators kan sende ut et avbrudd. A maximum of 8 timer blocks are supported for a total of 256 timers. Maksimalt 8 timer blokker støttes for totalt 256 tidtakere. Each timer block can have different clocking attributes. Hver blokk tidsur kan ha ulike stueklokke attributter. Specific implementations may include only a subset of these timers. Spesifikke implementeringer kan omfatte bare en undergruppe av disse tidtakere. A minimum of three timers is required. Minst tre timere er nødvendig.
The specification contains the following block diagram of the HPET architecture. Spesifikasjonen inneholder følgende blokkdiagram av HPET arkitektur.
Some of the timers may be enabled to generate a periodic interrupt. Noen av tidtakere kan bli i stand til å generere en periodisk avbryter. If a timer is set to be periodic, its period is added to the match register each time a match occurs, thus computing the next time for this timer to generate an interrupt.. Hvis en timer er satt til å være periodiske, er dens tid lagt til kampen registrere hver gang en kamp oppstår, og dermed beregne den neste tid for denne timeren for å generere et avbrudd .. An up-counter is usually 64 bits wide but 32-bit implementations are permitted by the specification and 64-bit up-counters can also be driven in 32-bit mode. En opp-telleren er vanligvis 64 bits brede, men 32-bits implementasjoner som er tillatt i spesifikasjonen og 64-bits up-tellere kan også være drevet i 32-biters modus. Up-counters run at a minimum of 10 MHz. Opp-tellere kjøre på minst 10 MHz. which is much faster than the older som er mye raskere enn de eldre RTC RTC (Real Time Clock) and can thus produce periodic interrupts at a much higher resolution. (Real Time Clock) og kan dermed produsere periodiske avbrudd på et mye høyere oppløsning. The registers associated with these timers are mapped to memory space. Registrene knyttet til disse timere er tilordnet plass i minnet.
The BIOS uses BIOS bruker ACPI ACPI ( Advanced Configuration and Power Interface) functionality to inform the operating system of the location of the HPET memory-mapped register space. (Advanced Configuration and Power Interface)-funksjonalitet for å informere operativsystemet på plasseringen av HPET minne-kartlegger register plass. Here is an example of a disassembled ACPI HPET table from an Intel DX48BT2 (AKA BoneTrail) motherboard. Her er et eksempel på en demontert ACPI HPET bord fra en Intel DX48BT2 (AKA BoneTrail) hovedkort.
$ cat /sys/firmware/acpi/tables/HPET > /var/tmp/hpet.out $ iasl -d /var/tmp/hpet.out $ cat /var/tmp/hpet.dsl /* * Intel ACPI Component Architecture * AML Disassembler version 20090123 * * Disassembly of /var/tmp/hpet.out, Sun Jul 5 19:34:47 2009 * * ACPI Data Table [HPET] * * Format: [HexOffset DecimalOffset ByteLength] FieldName : FieldValue */ [000h 000 4] Signature : "HPET" /* High Precision Event Timer table */ [004h 004 4] Table Length : 00000038 [008h 008 1] Revision : 01 [009h 009 1] Checksum : CE [00Ah 010 6] Oem ID : "INTEL " [010h 016 8] Oem Table ID : "DX48BT2 " [018h 024 4] Oem Revision : 0000076E [01Ch 028 4] Asl Compiler ID : "MSFT" [020h 032 4] Asl Compiler Revision : 01000013 [024h 036 4] Hardware Block ID : 8086A301 [028h 040 12] Timer Block Register :[028h 040 1] Space ID : 00 (SystemMemory) [029h 041 1] Bit Width : 00 [02Ah 042 1] Bit Offset : 00 [02Bh 043 1] Access Width : 00 [02Ch 044 8] Address : 00000000FED00000 [034h 052 1] Sequence Number : 00 [035h 053 2] Minimum Clock Ticks : 0001 [037h 055 1] Flags (decoded below) : 00 Page Protect : 0 4K Page Protect : 0 64K Page Protect : 0 Raw Table Data 0000: 48 50 45 54 38 00 00 00 01 CE 49 4E 54 45 4C 20 HPET8.....INTEL 0010: 44 58 34 38 42 54 32 20 6E 07 00 00 4D 53 46 54 DX48BT2 n...MSFT 0020: 13 00 00 01 01 A3 86 80 00 00 00 00 00 00 D0 FE ................ 0030: 00 00 00 00 00 01 00 00 ........ $
See page 30 of the HPET v1.0a specification for a detailed breakdown of the individual bits in the Event Time Block (called Hardware Block by the AML disassember). Se side 30 i HPET v1.0a spesifikasjonen for en detaljert oversikt over de enkelte biter i Event Time Block (kalt maskinvare Block av AML disassember). Note that only one Event Timer Block need be described in the HPET table in order to bootstrap an operating system. Merk at bare én hendelse TIMER-blokk må være beskrevet i HPET bordet for å bootstrap et operativsystem. This is the case here. Dette er tilfellet her. For non-legacy platforms, the Event Timer Block described in the HPET is the one that provides functionality to replace the 8254/RTC Periodic Interrupt Logic. For ikke-arven plattformer, Hendelse Timer Block beskrevet i HPET er den som gir funksjonalitet for å erstatte 8254/RTC Periodisk Interrupt Logic.
Other Event Time Blocks are described in the ACPI namespace. Andre Event Time Blokker er beskrevet i ACPI navnerommet. Here is the relevant section from the disassembled ACPI DSDT table. Her er den relevante delen fra demontert ACPI DSDT tabellen.
Device (HPET)
{
Name (_HID, EisaId ("PNP0103"))
Name (_CRS, ResourceTemplate ()
{
Memory32Fixed (ReadOnly,
0xFED00000, // Address Base
0x00004000, // Address Length
)
})
Method (_STA, 0, NotSerialized)
{
If (HPEE)
{
Return (0x0F)
}
Else
{
Return (Zero)
}
}
}
Note the assigned PNPID ( PNP0103 ) for the HPET. Legg merke til tildelt PNPID (PNP0103) for HPET. Because no _UID is specified it means that there are no other HPET timer blocks. Fordi ingen _UID er spesifisert det betyr at det ikke finnes andre HPET timer blokker.
Here is a list of the HPET-related messages outputted when this particular motherboard is booted up under Fedora 11. Her er en liste over HPET-relaterte meldinger outputted når dette hovedkortet er oppstartet opp under Fedora 11.
$ dmesg | grep -i HPET ACPI: HPET CFBF2000, 0038 (r1 INTEL DX48BT2 76E MSFT 1000013) ACPI: HPET id: 0x8086a301 base: 0xfed00000 hpet clockevent registered HPET: 4 timers in total, 0 timers will be used for per-cpu timer hpet0: at MMIO 0xfed00000, IRQs 2, 8, 0, 0 hpet0: 4 comparators, 64-bit 14.318180 MHz counter rtc0: alarms up to one month, 114 bytes nvram, hpet irqs $
The first line is outputted when the ACPI HPET table is read. Den første linjen outputted når ACPI HPET tabellen er lest. The second line is outputted when the ACPI HPET table is mapped into memory by …/arch/x86/kernel/acpi/boot.c . Den andre linjen er outputted når ACPI HPET tabellen er kartlagt i hukommelse etter ... / arch/x86/kernel/acpi/boot.c. The next line is outputted when the HPET legacy interrupts are started and HPET is registered as the global clock. Den neste linjen er outputted når HPET arv avbrudd er startet og HPET er registrert som den globale klokken. The following line is outputted when the kernel checks to ensure that at least one timer is reserved for userspace ( /dev/hpet .) The next two lines of output comes from the HPET device driver ( …/drivers/char/hpet.c .) It shows that 2 timers have allocated interrupts and two do not.. Følgende linje er outputted når kjernen sjekker for å sikre at minst ett timeren er reservert for userspace (/ dev / HPET.) De neste to linjene av produksjonen kommer fra HPET enhetsdriver (... / drivere / røye / hpet.c. ) Det viser at to timere har tildelt avbrudd og to ikke ..
Here is the relevant part of the output from /proc/time_list as it relates to HPET: Her er den relevante delen av produksjonen fra / proc / time_list som gjelder HPET:
Tick Device: mode: 1 Broadcast device Clock Event Device: hpet max_delta_ns: 149983005959 min_delta_ns: 5000 mult: 61496114 shift: 32 mode: 3 next_event: 9223372036854775807 nsecs set_next_event: hpet_legacy_next_event set_mode: hpet_legacy_set_mode event_handler: tick_handle_oneshot_broadcast tick_broadcast_mask: 00000000 tick_broadcast_oneshot_mask: 00000000
Here is the output from /proc/sys/dev/hpet and /proc/driver/rtc : Her er output fra / proc / sys / dev / HPET og / proc / driver / RTC:
$ cat /proc/sys/dev/hpet/max-user-freq 64 $ cat /proc/driver/rtc rtc_time : 06:34:31 rtc_date : 2009-07-06 alrm_time : **:24:40 alrm_date : ****-**-** alarm_IRQ : no alrm_pending : no 24hr : yes periodic_IRQ : no update_IRQ : no HPET_emulated : yes DST_enable : no periodic_freq : 1024 batt_status : okay
The HPET driver ( /dev/hpet ) has a similar API to the Real Time Clock driver. Den HPET driveren (/ dev / HPET) har et lignende API til Real Time Clock sjåfør. It is a character device which can support any number of HPET devices. Det er en karakter apparat som kan støtte en rekke HPET enheter. The kernel API has three interfaces exported from the driver: Kjernen API har tre grensesnitt eksportert fra driveren:
hpet_register( struct hpet_task *tp, int periodic ) hpet_unregister( struct hpet_task *tp ) hpet_control( struct hpet_task *tp, unsigned int cmd, unsigned long arg )
The userspace interface to HPET is defined in the header /usr/include/linux/hpet.h . Det userspace grensesnittet til HPET er definert i overskriften / usr / include / linux / hpet.h. The current set of supported operations is: Den nåværende sett av operasjoner som støttes er:
#define HPET_IE_ON _IO('h', 0x01) /* interrupt on */
#define HPET_IE_OFF _IO('h', 0x02) /* interrupt off */
#define HPET_INFO _IOR('h', 0x03, struct hpet_info) /* get information */
#define HPET_EPI _IO('h', 0x04) /* enable periodic */
#define HPET_DPI _IO('h', 0x05) /* disable periodic */
#define HPET_IRQFREQ _IOW('h', 0x6, unsigned long) /* set frequency */
The following example shows how to use the published interface to access a HPET and call a simple periodic signal handler hpet_alarm between 2 and 99 times a second. Følgende eksempel viser hvordan du bruker publiserte grensesnitt tilgang til en HPET og ringe en enkel periodisk signal behandleren hpet_alarm mellom 2 og 99 ganger i sekundet.
#include <stdio.h>
#include <stdlib.h;>
#include <fcntl.h>
#include <time.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <signal.h>
#include <fcntl.h>
#include <sys/time.h>
#include <linux/hpet.h>
#include <stdint.h>
#include <sys/ioctl.h>
#include <signal.h>
static uint16_t hpet_sigio_count;
static uint64_t secs;
static void
hpet_alarm(int val)
{
struct timespec t;
clock_gettime(CLOCK_REALTIME, &t);
if (!secs) secs = t.tv_sec;
fprintf(stderr, "hpet_alarm called. iteration: %2d secs: %ld nsecs: %ld \n",
hpet_sigio_count, (t.tv_sec - secs) , t.tv_sec * 100000 + t.tv_nsec );
hpet_sigio_count++;
}
int
main(int argc, const char **argv)
{
struct sigaction old, new;
struct hpet_info info;
int frequency;
int iterations;
int retval = 0;
int fd;
int r, i, value;
if (argc != 3) {
fprintf(stderr, "Usage: %s frequency(1-64) iterations(10-99)\n", argv[0]);
return -1;
}
frequency = atoi(argv[1]);
iterations = atoi(argv[2]);
if (frequency > 64 || frequency < 1 ) {
fprintf(stderr, "ERROR: Invalid value for frequency\n");
return -1;
}
if (iterations < 10 || iterations > 99 ) {
fprintf(stderr, "ERROR: Invalid value for iterations\n");
return -1;
}
hpet_sigio_count = 0;
sigemptyset(&new.sa_mask);
new.sa_flags = 0;
new.sa_handler = hpet_alarm;
sigaction(SIGIO, NULL, &old);
sigaction(SIGIO, &new, NULL);
fd = open("/dev/hpet", O_RDONLY);
if (fd < 0) {
fprintf(stderr, "ERROR: Failed to open /dev/hpet\n");
return -1;
}
if ((fcntl(fd, F_SETOWN, getpid()) == 1) ||
((value = fcntl(fd, F_GETFL)) == 1) ||
(fcntl(fd, F_SETFL, value | O_ASYNC) == 1)) {
fprintf(stderr, "ERROR: fcntl failed\n");
retval = 1;
goto fail;
}
if (ioctl(fd, HPET_IRQFREQ, frequency) < 0) {
fprintf(stderr, "ERROR: Could not set /dev/hpet to have a %2dHz timer\n", frequency);
retval = 2;
goto fail;
}
if (ioctl(fd, HPET_INFO, &info) < 0) {
fprintf(stderr, "ERROR: failed to get info\n");
retval = 3;
goto fail;
}
fprintf(stdout, "\nhi_ireqfreq: 0x%lx hi_flags: %0x%lx hi_hpet: 0x%x hi_timer: 0x%x\n\n",
info.hi_ireqfreq, info.hi_flags, info.hi_hpet, info.hi_timer);
r = ioctl(fd, HPET_EPI, 0);
if (info.hi_flags && (r < 0)) {
fprintf(stderr, "ERROR: HPET_EPI failed\n");
retval = 4;
goto fail;
}
if (ioctl(fd, HPET_IE_ON, 0) < 0) {
fprintf(stderr, "ERROR: HPET_IE_ON failed\n");
retval = 5;
goto fail;
}
/* wait for specified number of signal interrupts */
for (i = 0; i < iterations; i++) {
(void) pause();
}
if (ioctl(fd, HPET_IE_OFF, 0) < 0) {
fprintf(stderr, "ERROR: HPET_IE_OFF failed\n");
retval = 6;
}
fail:
sigaction(SIGIO, &old, NULL);
if (fd > 0)
close(fd);
return retval;
}
Here is the output from this example when it is invoked with a frequency of 32 and an iteration count of 64. Her er output fra dette eksemplet når den startes med en frekvens på 32 og en gjennomkøyring greve av 64.
$ sudo ./hpet_example 32 64 hi_ireqfreq: 0x20 hi_flags: 00 hi_hpet: 0x2 hi_timer: 0x4a1cb9c8 hpet_alarm called. iteration: 0 secs: 0 nsecs: 124683205055050 hpet_alarm called. iteration: 1 secs: 0 nsecs: 124683236313149 hpet_alarm called. iteration: 2 secs: 0 nsecs: 124683267566342 hpet_alarm called. iteration: 3 secs: 0 nsecs: 124683298821905 hpet_alarm called. iteration: 4 secs: 0 nsecs: 124683330077493 hpet_alarm called. iteration: 5 secs: 0 nsecs: 124683361341893 hpet_alarm called. iteration: 6 secs: 0 nsecs: 124683392590764 hpet_alarm called. iteration: 7 secs: 0 nsecs: 124683423849157 hpet_alarm called. iteration: 8 secs: 0 nsecs: 124683455101917 hpet_alarm called. iteration: 9 secs: 0 nsecs: 124683486357683 hpet_alarm called. iteration: 10 secs: 0 nsecs: 124683517617931 hpet_alarm called. iteration: 11 secs: 0 nsecs: 124683548872198 hpet_alarm called. iteration: 12 secs: 1 nsecs: 124682580229541 hpet_alarm called. iteration: 13 secs: 1 nsecs: 124682611481235 hpet_alarm called. iteration: 14 secs: 1 nsecs: 124682642740016 hpet_alarm called. iteration: 15 secs: 1 nsecs: 124682673992697 hpet_alarm called. iteration: 16 secs: 1 nsecs: 124682705247479 hpet_alarm called. iteration: 17 secs: 1 nsecs: 124682736504664 hpet_alarm called. iteration: 18 secs: 1 nsecs: 124682767758840 hpet_alarm called. iteration: 19 secs: 1 nsecs: 124682799014280 hpet_alarm called. iteration: 20 secs: 1 nsecs: 124682830270129 hpet_alarm called. iteration: 21 secs: 1 nsecs: 124682861530334 hpet_alarm called. iteration: 22 secs: 1 nsecs: 124682892784577 hpet_alarm called. iteration: 23 secs: 1 nsecs: 124682924038220 hpet_alarm called. iteration: 24 secs: 1 nsecs: 124682955294110 hpet_alarm called. iteration: 25 secs: 1 nsecs: 124682986550572 hpet_alarm called. iteration: 26 secs: 1 nsecs: 124683017805756 hpet_alarm called. iteration: 27 secs: 1 nsecs: 124683049061117 hpet_alarm called. iteration: 28 secs: 1 nsecs: 124683080318331 hpet_alarm called. iteration: 29 secs: 1 nsecs: 124683111576954 hpet_alarm called. iteration: 30 secs: 1 nsecs: 124683142828988 hpet_alarm called. iteration: 31 secs: 1 nsecs: 124683174083954 hpet_alarm called. iteration: 32 secs: 1 nsecs: 124683205337967 hpet_alarm called. iteration: 33 secs: 1 nsecs: 124683236593144 hpet_alarm called. iteration: 34 secs: 1 nsecs: 124683267851530 hpet_alarm called. iteration: 35 secs: 1 nsecs: 124683299104054 hpet_alarm called. iteration: 36 secs: 1 nsecs: 124683330358748 hpet_alarm called. iteration: 37 secs: 1 nsecs: 124683361617445 hpet_alarm called. iteration: 38 secs: 1 nsecs: 124683392870249 hpet_alarm called. iteration: 39 secs: 1 nsecs: 124683424124489 hpet_alarm called. iteration: 40 secs: 1 nsecs: 124683455379717 hpet_alarm called. iteration: 41 secs: 1 nsecs: 124683486634424 hpet_alarm called. iteration: 42 secs: 1 nsecs: 124683517889149 hpet_alarm called. iteration: 43 secs: 1 nsecs: 124683549144315 hpet_alarm called. iteration: 44 secs: 2 nsecs: 124682580500695 hpet_alarm called. iteration: 45 secs: 2 nsecs: 124682611761325 hpet_alarm called. iteration: 46 secs: 2 nsecs: 124682643011863 hpet_alarm called. iteration: 47 secs: 2 nsecs: 124682674265864 hpet_alarm called. iteration: 48 secs: 2 nsecs: 124682705521034 hpet_alarm called. iteration: 49 secs: 2 nsecs: 124682736776049 hpet_alarm called. iteration: 50 secs: 2 nsecs: 124682768030654 hpet_alarm called. iteration: 51 secs: 2 nsecs: 124682799285398 hpet_alarm called. iteration: 52 secs: 2 nsecs: 124682830544701 hpet_alarm called. iteration: 53 secs: 2 nsecs: 124682861797319 hpet_alarm called. iteration: 54 secs: 2 nsecs: 124682893051578 hpet_alarm called. iteration: 55 secs: 2 nsecs: 124682924306748 hpet_alarm called. iteration: 56 secs: 2 nsecs: 124682955562132 hpet_alarm called. iteration: 57 secs: 2 nsecs: 124682986823545 hpet_alarm called. iteration: 58 secs: 2 nsecs: 124683018073636 hpet_alarm called. iteration: 59 secs: 2 nsecs: 124683049327560 hpet_alarm called. iteration: 60 secs: 2 nsecs: 124683080586707 hpet_alarm called. iteration: 61 secs: 2 nsecs: 124683111841132 hpet_alarm called. iteration: 62 secs: 2 nsecs: 124683143095147 hpet_alarm called. iteration: 63 secs: 2 nsecs: 124683174349985 hpet_alarm called. iteration: 64 secs: 2 nsecs: 124683205607103 $
Well, I think that I have provided you with enough information so that you should now be able to go away and experiment with the HPET interface yourself. Vel, tror jeg at jeg har gitt deg nok informasjon slik at du skal nå kunne gå bort og eksperimentere med HPET grensesnittet selv.
By the way, not all VMware products support HPET. Forresten, ikke alle VMware-produkter støtter HPET. Currently ESX does not provide a virtual HPET to guest operating systems and in some cases it may be necessary to disable HPET altogether because of timer drift in virtual machines. Foreløpig ESX ikke gir et virtuelt HPET til gjestenes operativsystemer og i noen tilfeller kan det være nødvendig å deaktivere HPET helt på grunn av tidtaker drift i virtuelle maskiner. See Se VMware TimeKeeping VMware tidtaking for more information. for mer informasjon.
PS I tested the the above example on an Intel DX48BT2 motherboard running a 2.6.29.5-191 kernel. PS Jeg testet eksemplet ovenfor på en Intel DX48BT2 hovedkort kjører en 2.6.29.5-191 kjerne.
