diff options
Diffstat (limited to 'sys/x86')
| -rw-r--r-- | sys/x86/x86/tsc.c | 63 |
1 files changed, 60 insertions, 3 deletions
diff --git a/sys/x86/x86/tsc.c b/sys/x86/x86/tsc.c index 0994e9c..2a6c81d 100644 --- a/sys/x86/x86/tsc.c +++ b/sys/x86/x86/tsc.c @@ -65,6 +65,11 @@ int smp_tsc; SYSCTL_INT(_kern_timecounter, OID_AUTO, smp_tsc, CTLFLAG_RDTUN, &smp_tsc, 0, "Indicates whether the TSC is safe to use in SMP mode"); TUNABLE_INT("kern.timecounter.smp_tsc", &smp_tsc); + +int smp_tsc_adjust = 0; +SYSCTL_INT(_kern_timecounter, OID_AUTO, smp_tsc_adjust, CTLFLAG_RDTUN, + &smp_tsc_adjust, 0, "Try to adjust TSC on APs to match BSP"); +TUNABLE_INT("kern.timecounter.smp_tsc_adjust", &smp_tsc_adjust); #endif static int tsc_shift = 1; @@ -403,25 +408,77 @@ comp_smp_tsc(void *arg) } } +static void +adj_smp_tsc(void *arg) +{ + uint64_t *tsc; + int64_t d, min, max; + u_int cpu = PCPU_GET(cpuid); + u_int first, i, size; + + first = CPU_FIRST(); + if (cpu == first) + return; + min = INT64_MIN; + max = INT64_MAX; + size = (mp_maxid + 1) * 3; + for (i = 0, tsc = arg; i < N; i++, tsc += size) { + d = tsc[first * 3] - tsc[cpu * 3 + 1]; + if (d > min) + min = d; + d = tsc[first * 3 + 1] - tsc[cpu * 3 + 2]; + if (d > min) + min = d; + d = tsc[first * 3 + 1] - tsc[cpu * 3]; + if (d < max) + max = d; + d = tsc[first * 3 + 2] - tsc[cpu * 3 + 1]; + if (d < max) + max = d; + } + if (min > max) + return; + d = min / 2 + max / 2; + __asm __volatile ( + "movl $0x10, %%ecx\n\t" + "rdmsr\n\t" + "addl %%edi, %%eax\n\t" + "adcl %%esi, %%edx\n\t" + "wrmsr\n" + : /* No output */ + : "D" ((uint32_t)d), "S" ((uint32_t)(d >> 32)) + : "ax", "cx", "dx", "cc" + ); +} + static int test_tsc(void) { uint64_t *data, *tsc; - u_int i, size; + u_int i, size, adj; if ((!smp_tsc && !tsc_is_invariant) || vm_guest) return (-100); size = (mp_maxid + 1) * 3; data = malloc(sizeof(*data) * size * N, M_TEMP, M_WAITOK); + adj = 0; +retry: for (i = 0, tsc = data; i < N; i++, tsc += size) smp_rendezvous(tsc_read_0, tsc_read_1, tsc_read_2, tsc); smp_tsc = 1; /* XXX */ smp_rendezvous(smp_no_rendevous_barrier, comp_smp_tsc, smp_no_rendevous_barrier, data); + if (!smp_tsc && adj < smp_tsc_adjust) { + adj++; + smp_rendezvous(smp_no_rendevous_barrier, adj_smp_tsc, + smp_no_rendevous_barrier, data); + goto retry; + } free(data, M_TEMP); if (bootverbose) - printf("SMP: %sed TSC synchronization test\n", - smp_tsc ? "pass" : "fail"); + printf("SMP: %sed TSC synchronization test%s\n", + smp_tsc ? "pass" : "fail", + adj > 0 ? " after adjustment" : ""); if (smp_tsc && tsc_is_invariant) { switch (cpu_vendor_id) { case CPU_VENDOR_AMD: |
