why not clock_getres() ? Maxim.
On 02/08/17 05:37, Kevin Wang wrote: > Implement a new internal function timer_res_init() to detect the max > timer resolution without overrun at the ODP init stage. It will check > timer resolution from 1ms to 100us, 10us...1ns until the timer is > overrun. > > Signed-off-by: Kevin Wang <[email protected]> > --- > platform/linux-generic/odp_timer.c | 95 > ++++++++++++++++++++++++++++++++++++++ > 1 file changed, 95 insertions(+) > > diff --git a/platform/linux-generic/odp_timer.c > b/platform/linux-generic/odp_timer.c > index 53fec08..9b884ea 100644 > --- a/platform/linux-generic/odp_timer.c > +++ b/platform/linux-generic/odp_timer.c > @@ -70,6 +70,9 @@ static _odp_atomic_flag_t locks[NUM_LOCKS]; /* Multiple > locks per cache line! */ > #define IDX2LOCK(idx) (&locks[(idx) % NUM_LOCKS]) > #endif > > +/* Timer resolution in nanoseconds */ > +static uint64_t timer_res; > + > > /****************************************************************************** > * Translation between timeout buffer and timeout header > > *****************************************************************************/ > @@ -188,6 +191,7 @@ typedef struct odp_timer_pool_s { > > #define MAX_TIMER_POOLS 255 /* Leave one for ODP_TIMER_INVALID */ > #define INDEX_BITS 24 > +#define TIMER_RES_TEST_LOOP_COUNT 10 > static odp_atomic_u32_t num_timer_pools; > static odp_timer_pool *timer_pool[MAX_TIMER_POOLS]; > > @@ -738,6 +742,81 @@ static void *timer_thread(void *arg) > return NULL; > } > > +/* Get the max timer resolution without overrun and fill in timer_res > variable. > + * > + * Set timer's interval with candidate resolutions to get the max resolution > + * that the timer would not be overrun. > + * The candidate resolution value is from 1ms to 100us, 10us...1ns etc. > + */ > +static int timer_res_init(void) > +{ > + struct sigevent sigev; > + timer_t timerid; > + uint64_t res, sec, nsec; > + struct itimerspec ispec; > + sigset_t sigset; > + siginfo_t si; > + int loop_cnt; > + struct timespec tmo; > + > + sigev.sigev_notify = SIGEV_THREAD_ID; > + sigev._sigev_un._tid = (pid_t)syscall(SYS_gettid); > + sigev.sigev_signo = SIGUSR1; > + > + /* Create timer */ > + if (timer_create(CLOCK_MONOTONIC, &sigev, &timerid)) > + ODP_ABORT("timer_create() returned error %s\n", > + strerror(errno)); > + > + /* Timer resolution start from 1ms */ > + res = ODP_TIME_MSEC_IN_NS; > + /* Set initial value of timer_res */ > + timer_res = res; > + sigemptyset(&sigset); > + /* Add SIGUSR1 to sigset */ > + sigaddset(&sigset, SIGUSR1); > + sigprocmask(SIG_BLOCK, &sigset, NULL); > + > + while (res > 0) { > + /* Loop for 10 times to test the result */ > + loop_cnt = TIMER_RES_TEST_LOOP_COUNT; > + sec = res / ODP_TIME_SEC_IN_NS; > + nsec = res - sec * ODP_TIME_SEC_IN_NS; > + > + memset(&ispec, 0, sizeof(ispec)); > + ispec.it_interval.tv_sec = (time_t)sec; > + ispec.it_interval.tv_nsec = (long)nsec; > + ispec.it_value.tv_sec = (time_t)sec; > + ispec.it_value.tv_nsec = (long)nsec; > + > + if (timer_settime(timerid, 0, &ispec, NULL)) > + ODP_ABORT("timer_settime() returned error %s\n", > + strerror(errno)); > + /* Set signal wait timeout to 10*res */ > + tmo.tv_sec = 0; > + tmo.tv_nsec = res * 10; > + while (loop_cnt--) { > + if (sigtimedwait(&sigset, &si, &tmo) > 0) { > + if (timer_getoverrun(timerid)) > + /* overrun at this resolution */ > + /* goto the end */ > + goto timer_res_init_done; > + } > + } > + /* Set timer_res */ > + timer_res = res; > + /* Test the next timer resolution candidate */ > + res /= 10; > + } > +timer_res_init_done: > + if (timer_delete(timerid) != 0) > + ODP_ABORT("timer_delete() returned error %s\n", > + strerror(errno)); > + sigemptyset(&sigset); > + sigprocmask(SIG_BLOCK, &sigset, NULL); > + return 0; > +} > + > static void itimer_init(odp_timer_pool *tp) > { > struct sigevent sigev; > @@ -795,6 +874,20 @@ static void itimer_fini(odp_timer_pool *tp) > * Some parameter checks and error messages > * No modificatios of internal state > > *****************************************************************************/ > +int odp_timer_capability(odp_timer_clk_src_t clk_src, > + odp_timer_capability_t *capa) > +{ > + int ret = 0; > + > + if (clk_src == ODP_CLOCK_CPU) { > + capa->res_ns = timer_res; > + } else { > + ODP_ERR("ODP timer system doesn't support external clock source > currently\n"); > + ret = -1; > + } > + return ret; > +} > + > odp_timer_pool_t > odp_timer_pool_create(const char *name, > const odp_timer_pool_param_t *param) > @@ -1003,6 +1096,8 @@ int odp_timer_init_global(void) > #endif > odp_atomic_init_u32(&num_timer_pools, 0); > > + timer_res_init(); > + > block_sigalarm(); > > return 0; >
