diff options
| -rw-r--r-- | src/vppinfra/time.c | 15 | ||||
| -rw-r--r-- | src/vppinfra/time.h | 22 |
2 files changed, 19 insertions, 18 deletions
diff --git a/src/vppinfra/time.c b/src/vppinfra/time.c index 770ed8b6807..1626ff4ed38 100644 --- a/src/vppinfra/time.c +++ b/src/vppinfra/time.c @@ -142,17 +142,20 @@ done: f64 os_cpu_clock_frequency (void) { +#if defined (__aarch64__) + /* The system counter increments at a fixed frequency. It is distributed + * to each core which has registers for reading the current counter value + * as well as the clock frequency. The system counter is not clocked at + * the same frequency as the core. */ + u32 hz; + asm volatile ("mrs %0, cntfrq_el0":"=r" (hz)); + return (f64) hz; +#endif f64 cpu_freq; if (clib_cpu_supports_invariant_tsc ()) return estimate_clock_frequency (1e-3); -#if defined (__aarch64__) - u64 tsc; - asm volatile ("mrs %0, CNTFRQ_EL0":"=r" (tsc)); - return (f64) tsc; -#endif - /* First try /sys version. */ cpu_freq = clock_frequency_from_sys_filesystem (); if (cpu_freq != 0) diff --git a/src/vppinfra/time.h b/src/vppinfra/time.h index 288922d8a83..ead4b7d8ea4 100644 --- a/src/vppinfra/time.h +++ b/src/vppinfra/time.h @@ -114,6 +114,16 @@ clib_cpu_time_now (void) return (u64) lo + ((u64) hi2 << (u64) 32); } +#elif defined (__aarch64__) +always_inline u64 +clib_cpu_time_now (void) +{ + u64 vct; + /* User access to cntvct_el0 is enabled in Linux kernel since 3.12. */ + asm volatile ("mrs %0, cntvct_el0":"=r" (vct)); + return vct; +} + #elif defined (__arm__) #if defined(__ARM_ARCH_8A__) always_inline u64 @@ -164,18 +174,6 @@ clib_cpu_time_now (void) return ((u64) h << 32) | l; } -#elif defined (__aarch64__) -always_inline u64 -clib_cpu_time_now (void) -{ - u64 tsc; - - /* Works on Cavium ThunderX. Other platforms: YMMV */ - asm volatile ("mrs %0, cntvct_el0":"=r" (tsc)); - - return tsc; -} - #else #error "don't know how to read CPU time stamp" |