d/freebsd-dev
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Use atomic load & store for TSC frequency. It may be overkill for amd64 but

Browse Source 
safer for i386 because it can be easily over 4 GHz now.  More worse, it can
be easily changed by user with 'machdep.tsc_freq' tunable (directly) or
cpufreq(4) (indirectly).  Note it is intentionally not used in performance
critical paths to avoid performance regression (but we should, in theory).
Alternatively, we may add "virtual TSC" with lower frequency if maximum
frequency overflows 32 bits (and ignore possible incoherency as we do now).
This commit is contained in:
Jung-uk Kim 2011-04-07 23:28:28 +00:00
parent cb379161b1
commit 3453537fa5
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=220433
16 changed files with 78 additions and 54 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
sys/amd64/amd64/legacy.c
View File

@ -321,7 +321,8 @@ cpu_read_ivar(device_t dev, device_t child, int index, uintptr_t *result)
break;
case CPU_IVAR_NOMINAL_MHZ:
if (tsc_is_invariant) {
*result = (uintptr_t)(tsc_freq / 1000000);
*result = (uintptr_t)(atomic_load_acq_64(&tsc_freq) /
1000000);
break;
}
/* FALLTHROUGH */

11
sys/amd64/amd64/machdep.c
View File

@ -546,18 +546,19 @@ int
cpu_est_clockrate(int cpu_id, uint64_t *rate)
{
register_t reg;
uint64_t tsc1, tsc2;
uint64_t freq, tsc1, tsc2;
if (pcpu_find(cpu_id) == NULL || rate == NULL)
return (EINVAL);
freq = atomic_load_acq_64(&tsc_freq);
/* If TSC is P-state invariant, DELAY(9) based logic fails. */
if (tsc_is_invariant && tsc_freq != 0)
if (tsc_is_invariant && freq != 0)
return (EOPNOTSUPP);
/* If we're booting, trust the rate calibrated moments ago. */
if (cold && tsc_freq != 0) {
*rate = tsc_freq;
if (cold && freq != 0) {
*rate = freq;
return (0);
}
@ -586,7 +587,7 @@ cpu_est_clockrate(int cpu_id, uint64_t *rate)
#endif
tsc2 -= tsc1;
if (tsc_freq != 0) {
if (freq != 0) {
*rate = tsc2 * 1000;
return (0);
}

16
sys/amd64/amd64/prof_machdep.c
View File

@ -311,18 +311,22 @@ void
startguprof(gp)
struct gmonparam *gp;
{
uint64_t freq;
freq = atomic_load_acq_64(&tsc_freq);
if (cputime_clock == CPUTIME_CLOCK_UNINITIALIZED) {
cputime_clock = CPUTIME_CLOCK_I8254;
if (tsc_freq != 0 && mp_ncpus == 1)
if (freq != 0 && mp_ncpus == 1)
cputime_clock = CPUTIME_CLOCK_TSC;
else
cputime_clock = CPUTIME_CLOCK_I8254;
}
gp->profrate = i8254_freq << CPUTIME_CLOCK_I8254_SHIFT;
if (cputime_clock == CPUTIME_CLOCK_TSC) {
gp->profrate = tsc_freq >> 1;
gp->profrate = freq >> 1;
cputime_prof_active = 1;
}
} else
gp->profrate = i8254_freq << CPUTIME_CLOCK_I8254_SHIFT;
#if defined(PERFMON) && defined(I586_PMC_GUPROF)
else if (cputime_clock == CPUTIME_CLOCK_I586_PMC) {
if (cputime_clock == CPUTIME_CLOCK_I586_PMC) {
if (perfmon_avail() &&
perfmon_setup(0, cputime_clock_pmc_conf) == 0) {
if (perfmon_start(0) != 0)

2
sys/cddl/dev/dtrace/amd64/dtrace_subr.c
View File

@ -403,7 +403,7 @@ dtrace_gethrtime_init(void *arg)
* Otherwise tick->time conversion will be inaccurate, but
* will preserve monotonic property of TSC.
*/
tsc_f = tsc_freq;
tsc_f = atomic_load_acq_64(&tsc_freq);
/*
* The following line checks that nsec_scale calculated below

2
sys/cddl/dev/dtrace/i386/dtrace_subr.c
View File

@ -403,7 +403,7 @@ dtrace_gethrtime_init(void *arg)
* Otherwise tick->time conversion will be inaccurate, but
* will preserve monotonic property of TSC.
*/
tsc_f = tsc_freq;
tsc_f = atomic_load_acq_64(&tsc_freq);
/*
* The following line checks that nsec_scale calculated below

8
sys/compat/linprocfs/linprocfs.c
View File

@ -221,6 +221,7 @@ linprocfs_docpuinfo(PFS_FILL_ARGS)
{
int hw_model[2];
char model[128];
uint64_t freq;
size_t size;
int class, fqmhz, fqkhz;
int i;
@ -303,9 +304,10 @@ linprocfs_docpuinfo(PFS_FILL_ARGS)
if (cpu_feature & (1 << i))
sbuf_printf(sb, " %s", flags[i]);
sbuf_cat(sb, "\n");
if (class >= 5) {
fqmhz = (tsc_freq + 4999) / 1000000;
fqkhz = ((tsc_freq + 4999) / 10000) % 100;
freq = atomic_load_acq_64(&tsc_freq);
if (freq != 0) {
fqmhz = (freq + 4999) / 1000000;
fqkhz = ((freq + 4999) / 10000) % 100;
sbuf_printf(sb,
"cpu MHz\t\t: %d.%02d\n"
"bogomips\t: %d.%02d\n",

5
sys/contrib/altq/altq/altq_subr.c
View File

@ -929,7 +929,8 @@ init_machclk_setup(void)
#if defined(__amd64__) || defined(__i386__)
/* check if TSC is available */
#ifdef __FreeBSD__
if ((cpu_feature & CPUID_TSC) == 0 || tsc_freq == 0)
if ((cpu_feature & CPUID_TSC) == 0 ||
atomic_load_acq_64(&tsc_freq) == 0)
#else
if ((cpu_feature & CPUID_TSC) == 0)
#endif
@ -964,7 +965,7 @@ init_machclk(void)
*/
#if defined(__amd64__) || defined(__i386__)
#ifdef __FreeBSD__
machclk_freq = tsc_freq;
machclk_freq = atomic_load_acq_64(&tsc_freq);
#elif defined(__NetBSD__)
machclk_freq = (u_int32_t)cpu_tsc_freq;
#elif defined(__OpenBSD__) && (defined(I586_CPU) || defined(I686_CPU))

2
sys/dev/acpica/acpi_cpu.c
View File

@ -516,7 +516,7 @@ acpi_cpu_read_ivar(device_t dev, device_t child, int index, uintptr_t *result)
#if defined(__amd64__) || defined(__i386__)
case CPU_IVAR_NOMINAL_MHZ:
if (tsc_is_invariant) {
*result = (uintptr_t)(tsc_freq / 1000000);
*result = (uintptr_t)(atomic_load_acq_64(&tsc_freq) / 1000000);
break;
}
/* FALLTHROUGH */

3
sys/i386/i386/legacy.c
View File

@ -342,7 +342,8 @@ cpu_read_ivar(device_t dev, device_t child, int index, uintptr_t *result)
break;
case CPU_IVAR_NOMINAL_MHZ:
if (tsc_is_invariant) {
*result = (uintptr_t)(tsc_freq / 1000000);
*result = (uintptr_t)(atomic_load_acq_64(&tsc_freq) /
1000000);
break;
}
/* FALLTHROUGH */

11
sys/i386/i386/machdep.c
View File

@ -1137,20 +1137,21 @@ int
cpu_est_clockrate(int cpu_id, uint64_t *rate)
{
register_t reg;
uint64_t tsc1, tsc2;
uint64_t freq, tsc1, tsc2;
if (pcpu_find(cpu_id) == NULL || rate == NULL)
return (EINVAL);
if ((cpu_feature & CPUID_TSC) == 0)
return (EOPNOTSUPP);
freq = atomic_load_acq_64(&tsc_freq);
/* If TSC is P-state invariant, DELAY(9) based logic fails. */
if (tsc_is_invariant && tsc_freq != 0)
if (tsc_is_invariant && freq != 0)
return (EOPNOTSUPP);
/* If we're booting, trust the rate calibrated moments ago. */
if (cold && tsc_freq != 0) {
*rate = tsc_freq;
if (cold && freq != 0) {
*rate = freq;
return (0);
}
@ -1179,7 +1180,7 @@ cpu_est_clockrate(int cpu_id, uint64_t *rate)
#endif
tsc2 -= tsc1;
if (tsc_freq != 0) {
if (freq != 0) {
*rate = tsc2 * 1000;
return (0);
}

6
sys/i386/i386/perfmon.c
View File

@ -336,6 +336,7 @@ perfmon_ioctl(struct cdev *dev, u_long cmd, caddr_t param, int flags, struct thr
struct pmc *pmc;
struct pmc_data *pmcd;
struct pmc_tstamp *pmct;
uint64_t freq;
int *ip;
int rv;
@ -386,13 +387,14 @@ perfmon_ioctl(struct cdev *dev, u_long cmd, caddr_t param, int flags, struct thr
break;
case PMIOTSTAMP:
if (!tsc_freq) {
freq = atomic_load_acq_64(&tsc_freq);
if (freq == 0) {
rv = ENOTTY;
break;
}
pmct = (struct pmc_tstamp *)param;
/* XXX interface loses precision. */
pmct->pmct_rate = tsc_freq / 1000000;
pmct->pmct_rate = freq / 1000000;
pmct->pmct_value = rdtsc();
rv = 0;
break;

28
sys/i386/isa/prof_machdep.c
View File

@ -170,8 +170,8 @@ cputime()
{
u_int count;
int delta;
#if (defined(I586_CPU) || defined(I686_CPU)) && !defined(SMP) && \
defined(PERFMON) && defined(I586_PMC_GUPROF)
#if (defined(I586_CPU) || defined(I686_CPU)) && \
defined(PERFMON) && defined(I586_PMC_GUPROF) && !defined(SMP)
u_quad_t event_count;
#endif
u_char high, low;
@ -286,21 +286,23 @@ void
startguprof(gp)
struct gmonparam *gp;
{
#if defined(I586_CPU) || defined(I686_CPU)
uint64_t freq;
freq = atomic_load_acq_64(&tsc_freq);
if (cputime_clock == CPUTIME_CLOCK_UNINITIALIZED) {
cputime_clock = CPUTIME_CLOCK_I8254;
#if defined(I586_CPU) || defined(I686_CPU)
if (tsc_freq != 0 && mp_ncpus == 1)
if (freq != 0 && mp_ncpus == 1)
cputime_clock = CPUTIME_CLOCK_TSC;
#endif
else
cputime_clock = CPUTIME_CLOCK_I8254;
}
gp->profrate = i8254_freq << CPUTIME_CLOCK_I8254_SHIFT;
#if defined(I586_CPU) || defined(I686_CPU)
if (cputime_clock == CPUTIME_CLOCK_TSC) {
gp->profrate = tsc_freq >> 1;
gp->profrate = freq >> 1;
cputime_prof_active = 1;
}
} else
gp->profrate = i8254_freq << CPUTIME_CLOCK_I8254_SHIFT;
#if defined(PERFMON) && defined(I586_PMC_GUPROF)
else if (cputime_clock == CPUTIME_CLOCK_I586_PMC) {
if (cputime_clock == CPUTIME_CLOCK_I586_PMC) {
if (perfmon_avail() &&
perfmon_setup(0, cputime_clock_pmc_conf) == 0) {
if (perfmon_start(0) != 0)
@ -325,6 +327,10 @@ startguprof(gp)
}
}
#endif /* PERFMON && I586_PMC_GUPROF */
#else /* !(I586_CPU || I686_CPU) */
if (cputime_clock == CPUTIME_CLOCK_UNINITIALIZED)
cputime_clock = CPUTIME_CLOCK_I8254;
gp->profrate = i8254_freq << CPUTIME_CLOCK_I8254_SHIFT;
#endif /* I586_CPU || I686_CPU */
cputime_bias = 0;
cputime();

9
sys/pc98/pc98/machdep.c
View File

@ -1072,16 +1072,17 @@ int
cpu_est_clockrate(int cpu_id, uint64_t *rate)
{
register_t reg;
uint64_t tsc1, tsc2;
uint64_t freq, tsc1, tsc2;
if (pcpu_find(cpu_id) == NULL || rate == NULL)
return (EINVAL);
if ((cpu_feature & CPUID_TSC) == 0)
return (EOPNOTSUPP);
freq = atomic_load_acq_64(&tsc_freq);
/* If we're booting, trust the rate calibrated moments ago. */
if (cold && tsc_freq != 0) {
*rate = tsc_freq;
if (cold && freq != 0) {
*rate = freq;
return (0);
}
@ -1110,7 +1111,7 @@ cpu_est_clockrate(int cpu_id, uint64_t *rate)
#endif
tsc2 -= tsc1;
if (tsc_freq != 0) {
if (freq != 0) {
*rate = tsc2 * 1000;
return (0);
}

2
sys/x86/cpufreq/est.c
View File

@ -1215,7 +1215,7 @@ est_msr_info(device_t dev, uint64_t msr, freq_info **freqs)
return (EOPNOTSUPP);
/* Figure out the bus clock. */
freq = tsc_freq / 1000000;
freq = atomic_load_acq_64(&tsc_freq) / 1000000;
id = msr >> 32;
bus = freq / (id >> 8);
device_printf(dev, "Guessed bus clock (high) of %d MHz\n", bus);

10
sys/x86/isa/clock.c
View File

@ -246,13 +246,13 @@ getit(void)
}
static __inline void
delay_tsc(int n)
delay_tsc(int n, uint64_t freq)
{
uint64_t start, end, now;
sched_pin();
start = rdtsc();
end = start + (tsc_freq * n) / 1000000;
end = start + (freq * n) / 1000000;
do {
cpu_spinwait();
now = rdtsc();
@ -290,6 +290,7 @@ void
DELAY(int n)
{
struct timecounter *tc;
uint64_t freq;
int delta, prev_tick, tick, ticks_left;
#ifdef DELAYDEBUG
@ -298,8 +299,9 @@ DELAY(int n)
static int state = 0;
#endif
if (tsc_freq != 0) {
delay_tsc(n);
freq = atomic_load_acq_64(&tsc_freq);
if (freq != 0) {
delay_tsc(n, freq);
return;
}
tc = timecounter;

14
sys/x86/x86/tsc.c
View File

@ -245,14 +245,16 @@ tsc_freq_changing(void *arg, const struct cf_level *level, int *status)
static void
tsc_freq_changed(void *arg, const struct cf_level *level, int status)
{
uint64_t freq;
/* If there was an error during the transition, don't do anything. */
if (tsc_disabled || status != 0)
return;
/* Total setting for this level gives the new frequency in MHz. */
tsc_freq = (uint64_t)level->total_set.freq * 1000000;
tsc_timecounter.tc_frequency = tsc_freq;
freq = (uint64_t)level->total_set.freq * 1000000;
atomic_store_rel_64(&tsc_freq, freq);
atomic_store_rel_64(&tsc_timecounter.tc_frequency, freq);
}
static int
@ -261,13 +263,13 @@ sysctl_machdep_tsc_freq(SYSCTL_HANDLER_ARGS)
int error;
uint64_t freq;
if (tsc_timecounter.tc_frequency == 0)
freq = atomic_load_acq_64(&tsc_freq);
if (freq == 0)
return (EOPNOTSUPP);
freq = tsc_freq;
error = sysctl_handle_64(oidp, &freq, 0, req);
if (error == 0 && req->newptr != NULL) {
tsc_freq = freq;
tsc_timecounter.tc_frequency = tsc_freq;
atomic_store_rel_64(&tsc_freq, freq);
atomic_store_rel_64(&tsc_timecounter.tc_frequency, freq);
}
return (error);
}