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Probe capability to find effective frequency. When the TSC is P-state

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invariant, APERF/MPERF ratio can be used to find effective frequency.
This commit is contained in:
Jung-uk Kim 2011-04-12 22:15:46 +00:00
parent 3731174954
commit 155094d77a
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=220579
3 changed files with 17 additions and 2 deletions
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5
sys/amd64/amd64/identcpu.c
View File

@ -396,8 +396,11 @@ printcpuinfo(void)
* If this CPU supports P-state invariant TSC then
* mention the capability.
*/
if (tsc_is_invariant)
if (tsc_is_invariant) {
printf("\n TSC: P-state invariant");
if (tsc_perf_stat)
printf(", performance statistics");
}
}
}

5
sys/i386/i386/identcpu.c
View File

@ -873,8 +873,11 @@ printcpuinfo(void)
* If this CPU supports P-state invariant TSC then
* mention the capability.
*/
if (tsc_is_invariant)
if (tsc_is_invariant) {
printf("\n TSC: P-state invariant");
if (tsc_perf_stat)
printf(", performance statistics");
}
}
} else if (cpu_vendor_id == CPU_VENDOR_CYRIX) {

9
sys/x86/x86/tsc.c
View File

@ -49,6 +49,8 @@ __FBSDID("$FreeBSD$");
uint64_t tsc_freq;
int tsc_is_invariant;
int tsc_perf_stat;
static eventhandler_tag tsc_levels_tag, tsc_pre_tag, tsc_post_tag;
SYSCTL_INT(_kern_timecounter, OID_AUTO, invariant_tsc, CTLFLAG_RDTUN,
@ -151,6 +153,7 @@ tsc_freq_intel(void)
static void
probe_tsc_freq(void)
{
u_int regs[4];
uint64_t tsc1, tsc2;
switch (cpu_vendor_id) {
@ -178,6 +181,12 @@ probe_tsc_freq(void)
break;
}
if (cpu_high >= 6) {
do_cpuid(6, regs);
if ((regs[2] & CPUID_PERF_STAT) != 0)
tsc_perf_stat = 1;
}
if (tsc_skip_calibration) {
if (cpu_vendor_id == CPU_VENDOR_INTEL)
tsc_freq_intel();