Commit-ID: 37886f6a9f62d22530ffee8d3f9215c8345b6969
Gitweb: http://git.kernel.org/tip/37886f6a9f62d22530ffee8d3f9215c8345b6969
Author: Steven Rostedt <srostedt@xxxxxxxxxx>
AuthorDate: Tue, 17 Mar 2009 17:22:06 -0400
Commit: Steven Rostedt <srostedt@xxxxxxxxxx>
CommitDate: Tue, 17 Mar 2009 23:06:31 -0400
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@xxxxxxxxxx>
---
include/linux/ring_buffer.h | 7 +++-
kernel/trace/ring_buffer.c | 65 +++++++++++++++++++++++++------------------
kernel/trace/trace.c | 21 +++++++++----
3 files changed, 57 insertions(+), 36 deletions(-)
diff --git a/include/linux/ring_buffer.h b/include/linux/ring_buffer.h
index b1a0068..9e6052b 100644
--- a/include/linux/ring_buffer.h
+++ b/include/linux/ring_buffer.h
@@ -118,8 +118,11 @@ unsigned long ring_buffer_overruns(struct ring_buffer *buffer);
unsigned long ring_buffer_entries_cpu(struct ring_buffer *buffer, int cpu);
unsigned long ring_buffer_overrun_cpu(struct ring_buffer *buffer, int cpu);
-u64 ring_buffer_time_stamp(int cpu);
-void ring_buffer_normalize_time_stamp(int cpu, u64 *ts);
+u64 ring_buffer_time_stamp(struct ring_buffer *buffer, int cpu);
+void ring_buffer_normalize_time_stamp(struct ring_buffer *buffer,
+ int cpu, u64 *ts);
+void ring_buffer_set_clock(struct ring_buffer *buffer,
+ u64 (*clock)(void));
size_t ring_buffer_page_len(void *page);
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 58128ad..bbf5192 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -180,29 +180,6 @@ EXPORT_SYMBOL_GPL(tracing_is_on);
#include "trace.h"
-/* Up this if you want to test the TIME_EXTENTS and normalization */
-#define DEBUG_SHIFT 0
-
-u64 ring_buffer_time_stamp(int cpu)
-{
- u64 time;
-
- preempt_disable_notrace();
- /* shift to debug/test normalization and TIME_EXTENTS */
- time = trace_clock_local() << DEBUG_SHIFT;
- preempt_enable_no_resched_notrace();
-
- return time;
-}
-EXPORT_SYMBOL_GPL(ring_buffer_time_stamp);
-
-void ring_buffer_normalize_time_stamp(int cpu, u64 *ts)
-{
- /* Just stupid testing the normalize function and deltas */
- *ts >>= DEBUG_SHIFT;
-}
-EXPORT_SYMBOL_GPL(ring_buffer_normalize_time_stamp);
-
#define RB_EVNT_HDR_SIZE (offsetof(struct ring_buffer_event, array))
#define RB_ALIGNMENT 4U
#define RB_MAX_SMALL_DATA 28
@@ -374,6 +351,7 @@ struct ring_buffer {
#ifdef CONFIG_HOTPLUG_CPU
struct notifier_block cpu_notify;
#endif
+ u64 (*clock)(void);
};
struct ring_buffer_iter {
@@ -394,6 +372,30 @@ struct ring_buffer_iter {
_____ret; \
})
+/* Up this if you want to test the TIME_EXTENTS and normalization */
+#define DEBUG_SHIFT 0
+
+u64 ring_buffer_time_stamp(struct ring_buffer *buffer, int cpu)
+{
+ u64 time;
+
+ preempt_disable_notrace();
+ /* shift to debug/test normalization and TIME_EXTENTS */
+ time = buffer->clock() << DEBUG_SHIFT;
+ preempt_enable_no_resched_notrace();
+
+ return time;
+}
+EXPORT_SYMBOL_GPL(ring_buffer_time_stamp);
+
+void ring_buffer_normalize_time_stamp(struct ring_buffer *buffer,
+ int cpu, u64 *ts)
+{
+ /* Just stupid testing the normalize function and deltas */
+ *ts >>= DEBUG_SHIFT;
+}
+EXPORT_SYMBOL_GPL(ring_buffer_normalize_time_stamp);
+
/**
* check_pages - integrity check of buffer pages
* @cpu_buffer: CPU buffer with pages to test
@@ -569,6 +571,7 @@ struct ring_buffer *ring_buffer_alloc(unsigned long size, unsigned flags)
buffer->pages = DIV_ROUND_UP(size, BUF_PAGE_SIZE);
buffer->flags = flags;
+ buffer->clock = trace_clock_local;
/* need at least two pages */
if (buffer->pages == 1)
@@ -645,6 +648,12 @@ ring_buffer_free(struct ring_buffer *buffer)
}
EXPORT_SYMBOL_GPL(ring_buffer_free);
+void ring_buffer_set_clock(struct ring_buffer *buffer,
+ u64 (*clock)(void))
+{
+ buffer->clock = clock;
+}
+
static void rb_reset_cpu(struct ring_buffer_per_cpu *cpu_buffer);
static void
@@ -1191,7 +1200,7 @@ __rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer,
cpu_buffer->tail_page = next_page;
/* reread the time stamp */
- *ts = ring_buffer_time_stamp(cpu_buffer->cpu);
+ *ts = ring_buffer_time_stamp(buffer, cpu_buffer->cpu);
cpu_buffer->tail_page->page->time_stamp = *ts;
}
@@ -1334,7 +1343,7 @@ rb_reserve_next_event(struct ring_buffer_per_cpu *cpu_buffer,
if (RB_WARN_ON(cpu_buffer, ++nr_loops > 1000))
return NULL;
- ts = ring_buffer_time_stamp(cpu_buffer->cpu);
+ ts = ring_buffer_time_stamp(cpu_buffer->buffer, cpu_buffer->cpu);
/*
* Only the first commit can update the timestamp.
@@ -2051,7 +2060,8 @@ rb_buffer_peek(struct ring_buffer *buffer, int cpu, u64 *ts)
case RINGBUF_TYPE_DATA:
if (ts) {
*ts = cpu_buffer->read_stamp + event->time_delta;
- ring_buffer_normalize_time_stamp(cpu_buffer->cpu, ts);
+ ring_buffer_normalize_time_stamp(buffer,
+ cpu_buffer->cpu, ts);
}
return event;
@@ -2112,7 +2122,8 @@ rb_iter_peek(struct ring_buffer_iter *iter, u64 *ts)
case RINGBUF_TYPE_DATA:
if (ts) {
*ts = iter->read_stamp + event->time_delta;
- ring_buffer_normalize_time_stamp(cpu_buffer->cpu, ts);
+ ring_buffer_normalize_time_stamp(buffer,
+ cpu_buffer->cpu, ts);
}
return event;
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 8f89690..3be2f78 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -155,13 +155,6 @@ ns2usecs(cycle_t nsec)
return nsec;
}
-cycle_t ftrace_now(int cpu)
-{
- u64 ts = ring_buffer_time_stamp(cpu);
- ring_buffer_normalize_time_stamp(cpu, &ts);
- return ts;
-}
-
/*
* The global_trace is the descriptor that holds the tracing
* buffers for the live tracing. For each CPU, it contains
@@ -178,6 +171,20 @@ static struct trace_array global_trace;
static DEFINE_PER_CPU(struct trace_array_cpu, global_trace_cpu);
+cycle_t ftrace_now(int cpu)
+{
+ u64 ts;
+
+ /* Early boot up does not have a buffer yet */
+ if (!global_trace.buffer)
+ return trace_clock_local();
+
+ ts = ring_buffer_time_stamp(global_trace.buffer, cpu);
+ ring_buffer_normalize_time_stamp(global_trace.buffer, cpu, &ts);
+
+ return ts;
+}
+
/*
* The max_tr is used to snapshot the global_trace when a maximum
* latency is reached. Some tracers will use this to store a maximum
--
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