diff options
Diffstat (limited to 'kernel/trace')
| -rw-r--r-- | kernel/trace/trace_osnoise.c | 54 |
1 files changed, 53 insertions, 1 deletions
diff --git a/kernel/trace/trace_osnoise.c b/kernel/trace/trace_osnoise.c index dee610e465b9..78a4ee2e9c05 100644 --- a/kernel/trace/trace_osnoise.c +++ b/kernel/trace/trace_osnoise.c @@ -58,6 +58,7 @@ enum osnoise_options_index { OSN_PANIC_ON_STOP, OSN_PREEMPT_DISABLE, OSN_IRQ_DISABLE, + OSN_TIMERLAT_ALIGN, OSN_MAX }; @@ -66,7 +67,8 @@ static const char * const osnoise_options_str[OSN_MAX] = { "OSNOISE_WORKLOAD", "PANIC_ON_STOP", "OSNOISE_PREEMPT_DISABLE", - "OSNOISE_IRQ_DISABLE" }; + "OSNOISE_IRQ_DISABLE", + "TIMERLAT_ALIGN" }; #define OSN_DEFAULT_OPTIONS 0x2 static unsigned long osnoise_options = OSN_DEFAULT_OPTIONS; @@ -251,6 +253,11 @@ struct timerlat_variables { static DEFINE_PER_CPU(struct timerlat_variables, per_cpu_timerlat_var); /* + * timerlat wake-up offset for next thread with TIMERLAT_ALIGN set. + */ +static atomic64_t align_next; + +/* * this_cpu_tmr_var - Return the per-cpu timerlat_variables on its relative CPU */ static inline struct timerlat_variables *this_cpu_tmr_var(void) @@ -268,6 +275,7 @@ static inline void tlat_var_reset(void) /* Synchronize with the timerlat interfaces */ mutex_lock(&interface_lock); + /* * So far, all the values are initialized as 0, so * zeroing the structure is perfect. @@ -278,6 +286,12 @@ static inline void tlat_var_reset(void) hrtimer_cancel(&tlat_var->timer); memset(tlat_var, 0, sizeof(*tlat_var)); } + /* + * Reset also align_next, to be filled by a new offset by the first timerlat + * thread that wakes up, if TIMERLAT_ALIGN is set. + */ + atomic64_set(&align_next, 0); + mutex_unlock(&interface_lock); } #else /* CONFIG_TIMERLAT_TRACER */ @@ -326,6 +340,7 @@ static struct osnoise_data { u64 stop_tracing_total; /* stop trace in the final operation (report/thread) */ #ifdef CONFIG_TIMERLAT_TRACER u64 timerlat_period; /* timerlat period */ + u64 timerlat_align_us; /* timerlat alignment */ u64 print_stack; /* print IRQ stack if total > */ int timerlat_tracer; /* timerlat tracer */ #endif @@ -338,6 +353,7 @@ static struct osnoise_data { #ifdef CONFIG_TIMERLAT_TRACER .print_stack = 0, .timerlat_period = DEFAULT_TIMERLAT_PERIOD, + .timerlat_align_us = 0, .timerlat_tracer = 0, #endif }; @@ -1830,6 +1846,26 @@ static int wait_next_period(struct timerlat_variables *tlat) tlat->abs_period = (u64) ktime_to_ns(next_abs_period); /* + * Align thread in the first cycle on each CPU to the set alignment + * if TIMERLAT_ALIGN is set. + * + * This is done by using an atomic64_t to store the next absolute period. + * The first thread that wakes up will set the atomic64_t to its + * absolute period, and the other threads will increment it by + * the alignment value. + */ + if (test_bit(OSN_TIMERLAT_ALIGN, &osnoise_options) && !tlat->count + && atomic64_cmpxchg_relaxed(&align_next, 0, tlat->abs_period)) { + /* + * A thread has already set align_next, use it and increment it + * to be used by the next thread that wakes up after this one. + */ + tlat->abs_period = atomic64_add_return_relaxed( + osnoise_data.timerlat_align_us * 1000, &align_next); + next_abs_period = ns_to_ktime(tlat->abs_period); + } + + /* * If the new abs_period is in the past, skip the activation. */ while (ktime_compare(now, next_abs_period) > 0) { @@ -2650,6 +2686,17 @@ static struct trace_min_max_param timerlat_period = { .min = &timerlat_min_period, }; +/* + * osnoise/timerlat_align_us: align the first wakeup of all timerlat + * threads to a common boundary (in us). 0 means disabled. + */ +static struct trace_min_max_param timerlat_align_us = { + .lock = &interface_lock, + .val = &osnoise_data.timerlat_align_us, + .max = NULL, + .min = NULL, +}; + static const struct file_operations timerlat_fd_fops = { .open = timerlat_fd_open, .read = timerlat_fd_read, @@ -2746,6 +2793,11 @@ static int init_timerlat_tracefs(struct dentry *top_dir) if (!tmp) return -ENOMEM; + tmp = tracefs_create_file("timerlat_align_us", TRACE_MODE_WRITE, top_dir, + &timerlat_align_us, &trace_min_max_fops); + if (!tmp) + return -ENOMEM; + retval = osnoise_create_cpu_timerlat_fd(top_dir); if (retval) return retval; |