diff options
Diffstat (limited to 'sys/amd64/amd64/local_apic.c')
| -rw-r--r-- | sys/amd64/amd64/local_apic.c | 71 |
1 files changed, 43 insertions, 28 deletions
diff --git a/sys/amd64/amd64/local_apic.c b/sys/amd64/amd64/local_apic.c index 98ed4df..0d04bbd 100644 --- a/sys/amd64/amd64/local_apic.c +++ b/sys/amd64/amd64/local_apic.c @@ -160,6 +160,9 @@ static uint32_t lvt_mode(struct lapic *la, u_int pin, uint32_t value); struct pic lapic_pic = { .pic_resume = lapic_resume }; +static int lapic_allclocks; +TUNABLE_INT("machdep.lapic_allclocks", &lapic_allclocks); + static uint32_t lvt_mode(struct lapic *la, u_int pin, uint32_t value) { @@ -415,10 +418,11 @@ lapic_disable_pmc(void) /* * Called by cpu_initclocks() on the BSP to setup the local APIC timer so * that it can drive hardclock, statclock, and profclock. This function - * returns true if it is able to use the local APIC timer to drive the - * clocks and false if it is not able. + * returns a positive integer if it is convenient to use the local APIC + * for all the clocks, a negative integer if it is convenient to use the + * local APIC only for the hardclock and 0 if none of them can be handled. */ -int +enum lapic_clock lapic_setup_clock(void) { u_long value; @@ -426,10 +430,10 @@ lapic_setup_clock(void) /* Can't drive the timer without a local APIC. */ if (lapic == NULL) - return (0); + return (LAPIC_CLOCK_NONE); if (resource_int_value("apic", 0, "clock", &i) == 0 && i == 0) - return (0); + return (LAPIC_CLOCK_NONE); /* Start off with a divisor of 2 (power on reset default). */ lapic_timer_divisor = 2; @@ -461,19 +465,27 @@ lapic_setup_clock(void) * (and profhz) run at hz. If 'hz' is below 1500 but above * 750, then we let the lapic timer run at 2 * 'hz'. If 'hz' * is below 750 then we let the lapic timer run at 4 * 'hz'. + * + * Please note that stathz and profhz are set only if all the + * clocks are handled through the local APIC. */ - if (hz >= 1500) + if (lapic_allclocks != 0) { + if (hz >= 1500) + lapic_timer_hz = hz; + else if (hz >= 750) + lapic_timer_hz = hz * 2; + else + lapic_timer_hz = hz * 4; + } else lapic_timer_hz = hz; - else if (hz >= 750) - lapic_timer_hz = hz * 2; - else - lapic_timer_hz = hz * 4; - if (lapic_timer_hz < 128) - stathz = lapic_timer_hz; - else - stathz = lapic_timer_hz / (lapic_timer_hz / 128); - profhz = lapic_timer_hz; lapic_timer_period = value / lapic_timer_hz; + if (lapic_allclocks != 0) { + if (lapic_timer_hz < 128) + stathz = lapic_timer_hz; + else + stathz = lapic_timer_hz / (lapic_timer_hz / 128); + profhz = lapic_timer_hz; + } /* * Start up the timer on the BSP. The APs will kick off their @@ -481,7 +493,7 @@ lapic_setup_clock(void) */ lapic_timer_periodic(lapic_timer_period); lapic_timer_enable_intr(); - return (1); + return (lapic_allclocks == 0 ? LAPIC_CLOCK_HARDCLOCK : LAPIC_CLOCK_ALL); } void @@ -784,20 +796,23 @@ lapic_handle_timer(struct trapframe *frame) else hardclock_cpu(TRAPF_USERMODE(frame)); } + if (lapic_allclocks != 0) { - /* Fire statclock at stathz. */ - la->la_stat_ticks += stathz; - if (la->la_stat_ticks >= lapic_timer_hz) { - la->la_stat_ticks -= lapic_timer_hz; - statclock(TRAPF_USERMODE(frame)); - } + /* Fire statclock at stathz. */ + la->la_stat_ticks += stathz; + if (la->la_stat_ticks >= lapic_timer_hz) { + la->la_stat_ticks -= lapic_timer_hz; + statclock(TRAPF_USERMODE(frame)); + } - /* Fire profclock at profhz, but only when needed. */ - la->la_prof_ticks += profhz; - if (la->la_prof_ticks >= lapic_timer_hz) { - la->la_prof_ticks -= lapic_timer_hz; - if (profprocs != 0) - profclock(TRAPF_USERMODE(frame), TRAPF_PC(frame)); + /* Fire profclock at profhz, but only when needed. */ + la->la_prof_ticks += profhz; + if (la->la_prof_ticks >= lapic_timer_hz) { + la->la_prof_ticks -= lapic_timer_hz; + if (profprocs != 0) + profclock(TRAPF_USERMODE(frame), + TRAPF_PC(frame)); + } } critical_exit(); } |
