ring-buffer: add api to allow a tracer to change clock source
This patch adds a new function called ring_buffer_set_clock that allows a tracer to assign its own clock source to the buffer. Signed-off-by: Steven Rostedt <srostedt@redhat.com>hifive-unleashed-5.1
parent
6adaad14d7
commit
37886f6a9f
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@ -118,8 +118,11 @@ unsigned long ring_buffer_overruns(struct ring_buffer *buffer);
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unsigned long ring_buffer_entries_cpu(struct ring_buffer *buffer, int cpu);
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unsigned long ring_buffer_entries_cpu(struct ring_buffer *buffer, int cpu);
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unsigned long ring_buffer_overrun_cpu(struct ring_buffer *buffer, int cpu);
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unsigned long ring_buffer_overrun_cpu(struct ring_buffer *buffer, int cpu);
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u64 ring_buffer_time_stamp(int cpu);
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u64 ring_buffer_time_stamp(struct ring_buffer *buffer, int cpu);
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void ring_buffer_normalize_time_stamp(int cpu, u64 *ts);
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void ring_buffer_normalize_time_stamp(struct ring_buffer *buffer,
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int cpu, u64 *ts);
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void ring_buffer_set_clock(struct ring_buffer *buffer,
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u64 (*clock)(void));
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size_t ring_buffer_page_len(void *page);
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size_t ring_buffer_page_len(void *page);
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@ -180,29 +180,6 @@ EXPORT_SYMBOL_GPL(tracing_is_on);
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#include "trace.h"
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#include "trace.h"
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/* Up this if you want to test the TIME_EXTENTS and normalization */
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#define DEBUG_SHIFT 0
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u64 ring_buffer_time_stamp(int cpu)
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{
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u64 time;
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preempt_disable_notrace();
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/* shift to debug/test normalization and TIME_EXTENTS */
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time = trace_clock_local() << DEBUG_SHIFT;
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preempt_enable_no_resched_notrace();
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return time;
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}
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EXPORT_SYMBOL_GPL(ring_buffer_time_stamp);
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void ring_buffer_normalize_time_stamp(int cpu, u64 *ts)
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{
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/* Just stupid testing the normalize function and deltas */
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*ts >>= DEBUG_SHIFT;
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}
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EXPORT_SYMBOL_GPL(ring_buffer_normalize_time_stamp);
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#define RB_EVNT_HDR_SIZE (offsetof(struct ring_buffer_event, array))
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#define RB_EVNT_HDR_SIZE (offsetof(struct ring_buffer_event, array))
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#define RB_ALIGNMENT 4U
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#define RB_ALIGNMENT 4U
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#define RB_MAX_SMALL_DATA 28
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#define RB_MAX_SMALL_DATA 28
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@ -374,6 +351,7 @@ struct ring_buffer {
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#ifdef CONFIG_HOTPLUG_CPU
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#ifdef CONFIG_HOTPLUG_CPU
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struct notifier_block cpu_notify;
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struct notifier_block cpu_notify;
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#endif
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#endif
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u64 (*clock)(void);
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};
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};
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struct ring_buffer_iter {
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struct ring_buffer_iter {
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@ -394,6 +372,30 @@ struct ring_buffer_iter {
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_____ret; \
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_____ret; \
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})
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})
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/* Up this if you want to test the TIME_EXTENTS and normalization */
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#define DEBUG_SHIFT 0
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u64 ring_buffer_time_stamp(struct ring_buffer *buffer, int cpu)
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{
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u64 time;
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preempt_disable_notrace();
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/* shift to debug/test normalization and TIME_EXTENTS */
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time = buffer->clock() << DEBUG_SHIFT;
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preempt_enable_no_resched_notrace();
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return time;
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}
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EXPORT_SYMBOL_GPL(ring_buffer_time_stamp);
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void ring_buffer_normalize_time_stamp(struct ring_buffer *buffer,
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int cpu, u64 *ts)
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{
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/* Just stupid testing the normalize function and deltas */
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*ts >>= DEBUG_SHIFT;
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}
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EXPORT_SYMBOL_GPL(ring_buffer_normalize_time_stamp);
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/**
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/**
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* check_pages - integrity check of buffer pages
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* check_pages - integrity check of buffer pages
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* @cpu_buffer: CPU buffer with pages to test
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* @cpu_buffer: CPU buffer with pages to test
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@ -569,6 +571,7 @@ struct ring_buffer *ring_buffer_alloc(unsigned long size, unsigned flags)
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buffer->pages = DIV_ROUND_UP(size, BUF_PAGE_SIZE);
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buffer->pages = DIV_ROUND_UP(size, BUF_PAGE_SIZE);
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buffer->flags = flags;
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buffer->flags = flags;
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buffer->clock = trace_clock_local;
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/* need at least two pages */
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/* need at least two pages */
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if (buffer->pages == 1)
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if (buffer->pages == 1)
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@ -645,6 +648,12 @@ ring_buffer_free(struct ring_buffer *buffer)
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}
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}
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EXPORT_SYMBOL_GPL(ring_buffer_free);
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EXPORT_SYMBOL_GPL(ring_buffer_free);
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void ring_buffer_set_clock(struct ring_buffer *buffer,
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u64 (*clock)(void))
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{
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buffer->clock = clock;
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}
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static void rb_reset_cpu(struct ring_buffer_per_cpu *cpu_buffer);
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static void rb_reset_cpu(struct ring_buffer_per_cpu *cpu_buffer);
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static void
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static void
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@ -1191,7 +1200,7 @@ __rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer,
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cpu_buffer->tail_page = next_page;
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cpu_buffer->tail_page = next_page;
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/* reread the time stamp */
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/* reread the time stamp */
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*ts = ring_buffer_time_stamp(cpu_buffer->cpu);
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*ts = ring_buffer_time_stamp(buffer, cpu_buffer->cpu);
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cpu_buffer->tail_page->page->time_stamp = *ts;
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cpu_buffer->tail_page->page->time_stamp = *ts;
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}
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}
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@ -1334,7 +1343,7 @@ rb_reserve_next_event(struct ring_buffer_per_cpu *cpu_buffer,
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if (RB_WARN_ON(cpu_buffer, ++nr_loops > 1000))
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if (RB_WARN_ON(cpu_buffer, ++nr_loops > 1000))
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return NULL;
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return NULL;
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ts = ring_buffer_time_stamp(cpu_buffer->cpu);
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ts = ring_buffer_time_stamp(cpu_buffer->buffer, cpu_buffer->cpu);
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/*
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/*
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* Only the first commit can update the timestamp.
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* Only the first commit can update the timestamp.
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@ -2051,7 +2060,8 @@ rb_buffer_peek(struct ring_buffer *buffer, int cpu, u64 *ts)
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case RINGBUF_TYPE_DATA:
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case RINGBUF_TYPE_DATA:
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if (ts) {
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if (ts) {
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*ts = cpu_buffer->read_stamp + event->time_delta;
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*ts = cpu_buffer->read_stamp + event->time_delta;
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ring_buffer_normalize_time_stamp(cpu_buffer->cpu, ts);
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ring_buffer_normalize_time_stamp(buffer,
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cpu_buffer->cpu, ts);
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}
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}
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return event;
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return event;
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@ -2112,7 +2122,8 @@ rb_iter_peek(struct ring_buffer_iter *iter, u64 *ts)
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case RINGBUF_TYPE_DATA:
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case RINGBUF_TYPE_DATA:
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if (ts) {
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if (ts) {
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*ts = iter->read_stamp + event->time_delta;
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*ts = iter->read_stamp + event->time_delta;
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ring_buffer_normalize_time_stamp(cpu_buffer->cpu, ts);
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ring_buffer_normalize_time_stamp(buffer,
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cpu_buffer->cpu, ts);
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}
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}
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return event;
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return event;
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@ -155,13 +155,6 @@ ns2usecs(cycle_t nsec)
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return nsec;
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return nsec;
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}
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}
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cycle_t ftrace_now(int cpu)
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{
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u64 ts = ring_buffer_time_stamp(cpu);
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ring_buffer_normalize_time_stamp(cpu, &ts);
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return ts;
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}
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/*
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/*
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* The global_trace is the descriptor that holds the tracing
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* The global_trace is the descriptor that holds the tracing
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* buffers for the live tracing. For each CPU, it contains
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* buffers for the live tracing. For each CPU, it contains
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@ -178,6 +171,20 @@ static struct trace_array global_trace;
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static DEFINE_PER_CPU(struct trace_array_cpu, global_trace_cpu);
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static DEFINE_PER_CPU(struct trace_array_cpu, global_trace_cpu);
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cycle_t ftrace_now(int cpu)
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{
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u64 ts;
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/* Early boot up does not have a buffer yet */
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if (!global_trace.buffer)
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return trace_clock_local();
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ts = ring_buffer_time_stamp(global_trace.buffer, cpu);
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ring_buffer_normalize_time_stamp(global_trace.buffer, cpu, &ts);
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return ts;
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}
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/*
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/*
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* The max_tr is used to snapshot the global_trace when a maximum
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* The max_tr is used to snapshot the global_trace when a maximum
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* latency is reached. Some tracers will use this to store a maximum
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* latency is reached. Some tracers will use this to store a maximum
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