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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Minios-devel] [UNIKRAFT PATCH v5] plat/*: Make timer interrupt frequency selectable
Reviewed-by: Yuri Volchkov <yuri.volchkov@xxxxxxxxx>
Florian Schmidt <florian.schmidt@xxxxxxxxx> writes:
> Add new configuration options for choosing a timer interrupt frequency.
> The configured frequency is converted to the timer tick length which can
> be of use for other modules (e.g., preemptive schedulers).
>
> Previously, the tick was 100 Hz on KVM and 1000 Hz on Xen. The default
> value is now 100 Hz across both platforms.
>
> Signed-off-by: Costin Lupu <costin.lupu@xxxxxxxxx>
> Signed-off-by: Florian Schmidt <florian.schmidt@xxxxxxxxx>
> ---
> include/uk/arch/time.h | 6 ++++--
> include/uk/plat/time.h | 4 ++++
> plat/Config.uk | 8 ++++++++
> plat/kvm/x86/tscclock.c | 29 ++++++++++++++++++-----------
> plat/linuxu/include/linuxu/time.h | 3 ++-
> plat/linuxu/time.c | 2 --
> plat/xen/x86/arch_time.c | 2 +-
> 7 files changed, 37 insertions(+), 17 deletions(-)
>
> diff --git a/include/uk/arch/time.h b/include/uk/arch/time.h
> index 262fd3b1..ac207887 100644
> --- a/include/uk/arch/time.h
> +++ b/include/uk/arch/time.h
> @@ -57,12 +57,14 @@ typedef __s64 __snsec;
> #define __SNSEC_MAX (__S64_MAX)
> #define __SNSEC_MIN (__S64_MIN)
>
> -#define ukarch_time_nsec_to_sec(ns) ((ns) / 1000000000ULL)
> +#define UKARCH_NSEC_PER_SEC 1000000000ULL
> +
> +#define ukarch_time_nsec_to_sec(ns) ((ns) / UKARCH_NSEC_PER_SEC)
> #define ukarch_time_nsec_to_msec(ns) ((ns) / 1000000ULL)
> #define ukarch_time_nsec_to_usec(ns) ((ns) / 1000UL)
> #define ukarch_time_subsec(ns) ((ns) % 1000000000ULL)
>
> -#define ukarch_time_sec_to_nsec(sec) ((sec) * 1000000000UL)
> +#define ukarch_time_sec_to_nsec(sec) ((sec) * UKARCH_NSEC_PER_SEC)
> #define ukarch_time_msec_to_nsec(msec) ((msec) * 1000000UL)
> #define ukarch_time_usec_to_nsec(usec) ((usec) * 1000UL)
>
> diff --git a/include/uk/plat/time.h b/include/uk/plat/time.h
> index 202e0f99..b402ec24 100644
> --- a/include/uk/plat/time.h
> +++ b/include/uk/plat/time.h
> @@ -47,6 +47,10 @@ void ukplat_time_fini(void);
>
> __nsec ukplat_monotonic_clock(void);
>
> +/* Time tick length */
> +#define UKPLAT_TIME_TICK_NSEC (UKARCH_NSEC_PER_SEC / CONFIG_HZ)
> +#define UKPLAT_TIME_TICK_MSEC
> ukarch_time_nsec_to_msec(UKPLAT_TIME_TICK_NSEC)
> +
> #ifdef __cplusplus
> }
> #endif
> diff --git a/plat/Config.uk b/plat/Config.uk
> index b776c451..8a878eb0 100644
> --- a/plat/Config.uk
> +++ b/plat/Config.uk
> @@ -17,3 +17,11 @@ config EARLY_PRINT_PL011_UART_ADDR
> Pl011 serial address used by early debug console.
>
> endmenu
> +
> +config HZ
> + int
> + prompt "Timer frequency (Hz)"
> + default 100
> + help
> + Configure the timer interrupt frequency.
> + Only change this if you know what you're doing.
> diff --git a/plat/kvm/x86/tscclock.c b/plat/kvm/x86/tscclock.c
> index f3fa55a2..86db814a 100644
> --- a/plat/kvm/x86/tscclock.c
> +++ b/plat/kvm/x86/tscclock.c
> @@ -60,8 +60,6 @@
> #include <uk/assert.h>
> #include <uk/bitops.h>
>
> -#define NSEC_PER_SEC 1000000000ULL
> -
> #define TIMER_CNTR 0x40
> #define TIMER_MODE 0x43
> #define TIMER_SEL0 0x00
> @@ -84,6 +82,15 @@
> #define RTC_STATUS_A 0x0a
> #define RTC_UIP (1<<7)
>
> +/*
> + * Compile-time check to make sure we don't tick faster than the PIT can go.
> + * This is really only a basic sanity check. We'll run into serious issues
> WAY
> + * earlier.
> + */
> +#if TIMER_HZ / CONFIG_HZ < 1
> +#error Timer tick frequency (CONFIG_HZ) cannot be higher than PIT frequency!
> +#endif
> +
> /* RTC wall time offset at monotonic time base. */
> static __u64 rtc_epochoffset;
>
> @@ -103,11 +110,11 @@ static __u32 tsc_mult;
> *
> * Calculated as:
> *
> - * f = NSEC_PER_SEC / TIMER_HZ (0.31) fixed point.
> - * pit_mult = 1 / f (1.32) fixed point.
> + * f = UKARCH_NSEC_PER_SEC / TIMER_HZ (0.31) fixed point.
> + * pit_mult = 1 / f (1.32) fixed point.
> */
> static const __u32 pit_mult =
> - (1ULL << 63) / ((NSEC_PER_SEC << 31) / TIMER_HZ);
> + (1ULL << 63) / ((UKARCH_NSEC_PER_SEC << 31) / TIMER_HZ);
>
>
> /*
> @@ -131,7 +138,7 @@ static void i8254_delay(unsigned int n)
> {
> unsigned int cur_tick, initial_tick;
> int remaining;
> - const unsigned long timer_rval = TIMER_HZ / 100;
> + const unsigned long timer_rval = TIMER_HZ / CONFIG_HZ;
>
> initial_tick = i8254_gettick();
>
> @@ -211,10 +218,10 @@ int tscclock_init(void)
> {
> __u64 tsc_freq, rtc_boot;
>
> - /* Initialise i8254 timer channel 0 to mode 2 at 100 Hz */
> + /* Initialise i8254 timer channel 0 to mode 2 at CONFIG_HZ frequency */
> outb(TIMER_MODE, TIMER_SEL0 | TIMER_RATEGEN | TIMER_16BIT);
> - outb(TIMER_CNTR, (TIMER_HZ / 100) & 0xff);
> - outb(TIMER_CNTR, (TIMER_HZ / 100) >> 8);
> + outb(TIMER_CNTR, (TIMER_HZ / CONFIG_HZ) & 0xff);
> + outb(TIMER_CNTR, (TIMER_HZ / CONFIG_HZ) >> 8);
>
> /*
> * Read RTC "time at boot". This must be done just before tsc_base is
> @@ -238,9 +245,9 @@ int tscclock_init(void)
> /*
> * Calculate TSC scaling multiplier.
> *
> - * (0.32) tsc_mult = NSEC_PER_SEC (32.32) / tsc_freq (32.0)
> + * (0.32) tsc_mult = UKARCH_NSEC_PER_SEC (32.32) / tsc_freq (32.0)
> */
> - tsc_mult = (NSEC_PER_SEC << 32) / tsc_freq;
> + tsc_mult = (UKARCH_NSEC_PER_SEC << 32) / tsc_freq;
>
> /*
> * Monotonic time begins at tsc_base (first read of TSC before
> diff --git a/plat/linuxu/include/linuxu/time.h
> b/plat/linuxu/include/linuxu/time.h
> index 2df881ec..c1a875af 100644
> --- a/plat/linuxu/include/linuxu/time.h
> +++ b/plat/linuxu/include/linuxu/time.h
> @@ -35,9 +35,10 @@
> #ifndef __LINUXU_TIME_H__
> #define __LINUXU_TIME_H__
>
> +#include <uk/plat/time.h>
> #include <linuxu/signal.h>
>
> -#define TIMER_INTVAL_MSEC 10
> +#define TIMER_INTVAL_NSEC UKPLAT_TIME_TICK_NSEC
> #define TIMER_SIGNUM SIGALRM
>
>
> diff --git a/plat/linuxu/time.c b/plat/linuxu/time.c
> index ead07f59..13439ad5 100644
> --- a/plat/linuxu/time.c
> +++ b/plat/linuxu/time.c
> @@ -40,8 +40,6 @@
> #include <linuxu/syscall.h>
> #include <linuxu/time.h>
>
> -#define TIMER_INTVAL_NSEC ukarch_time_msec_to_nsec(TIMER_INTVAL_MSEC)
> -
> static k_timer_t timerid;
>
>
> diff --git a/plat/xen/x86/arch_time.c b/plat/xen/x86/arch_time.c
> index 95d7b103..a4b77b93 100644
> --- a/plat/xen/x86/arch_time.c
> +++ b/plat/xen/x86/arch_time.c
> @@ -233,7 +233,7 @@ void time_block_until(__snsec until)
> static void timer_handler(evtchn_port_t ev __unused,
> struct __regs *regs __unused, void *ign __unused)
> {
> - __nsec until = ukplat_monotonic_clock() + ukarch_time_msec_to_nsec(1);
> + __nsec until = ukplat_monotonic_clock() + UKPLAT_TIME_TICK_NSEC;
>
> HYPERVISOR_set_timer_op(until);
> }
> --
> 2.20.1
>
--
Yuri Volchkov
Software Specialist
NEC Europe Ltd
Kurfürsten-Anlage 36
D-69115 Heidelberg
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