Add memory sample feature (#541)

* Add memory sampling feature.

Currently only gets 10 samples per second, but the overall scaffolding
looks like it works.

Change-Id: I25a2bbcba322f2101c3de598c225f83c902680fa

* Basic memory sample speed-ups.

977 samples/second.

Change-Id: I6ea874f25051aca1cbe3aa2918567a4ee316c4be

* Add base64 dumping of sample buffer.

We can't just dump raw data, because the API we use to get data to the
"user" uses NULL-terminated strings.

Change-Id: I3f33faaa485a74735c13cdaad685e336c1e2095f

* WIP on optimizing PC sampling.

1k samples per second on my laptop, which is roughly double what it was.

Change-Id: I6a77df8aa53118e44928f96d22210df84be45eda

* WIP

Change-Id: I4300692355cb0cf997ec59ab5ca71543b295abb0

* Use small batch to sample memory.

5k samples/second. No error checking.

Change-Id: I8a7f08e49cb153699021e27f8006beb0e6db70ee

* Collect memory samples near continuously.

Rewrite OpenOCD's core loop to get rid of the fixed 100ms delay.
Now collecting 15k samples/second.

Change-Id: Iba5e73e96e8d226a0b5777ecac19453c152dc634

* Fix build.

Change-Id: If2fe7a0c77e0d6545c93fa0d4a013c50a9b9d896

* Fix the mess I left after resolving conflicts.

Change-Id: I96abd47a7834bf8f5e005ba63020f0a0cc429548

* Support 64-bit address in memory sampling.

* Support sampling 64-bit values.

* Better error reporting. WIP on 64-bit support.

* Speed up single 32-bit memory sample.

21k samples/second.

* WIP on review feedback.

Change-Id: I00e453fd685d173b0206d925090beb06c1f057ca

* Make memory sample buffers/config per-target.

Change-Id: I5c2f5997795c7a434e71b36ca4c712623daf993c

* Document, and add bucket clear option.

Change-Id: I922b883adfa787fb4f5a894db872d04fda126cbd
Signed-off-by: Tim Newsome <tim@sifive.com>

* Fix whitespace.

Change-Id: Iabfeb0068d7138d9b252ac127d1b1f949cf19632
Signed-off-by: Tim Newsome <tim@sifive.com>

* Document sample buffer full behavior.

Change-Id: Ib3c30d34b1f9f30cf403afda8fdccb850bc8b4df
Signed-off-by: Tim Newsome <tim@sifive.com>

* Actually clear the sample buffer in dump_sample_buf.

Change-Id: Ifda22643f1e58f69a6382abc90474659d7330ac5
Signed-off-by: Tim Newsome <tim@sifive.com>

* Use compatible string formatting.

Change-Id: Ia5e5333e036c1dbe457bc977fcee41983b9a9b77
Signed-off-by: Tim Newsome <tim@sifive.com>

1 files changed, 22 insertions, 16 deletions

diff --git a/src/target/target.c b/src/target/target.c
index 3395b2a..ca1ded3 100644
--- a/src/target/target.c
+++ b/src/target/target.c
@@ -158,7 +158,7 @@ static struct target_event_callback *target_event_callbacks;
 static struct target_timer_callback *target_timer_callbacks;
 LIST_HEAD(target_reset_callback_list);
 LIST_HEAD(target_trace_callback_list);
-static const int polling_interval = 100;
+static const int polling_interval = TARGET_DEFAULT_POLLING_INTERVAL;
 
 static const Jim_Nvp nvp_assert[] = {
 	{ .name = "assert", NVP_ASSERT },
@@ -674,7 +674,7 @@ static int target_process_reset(struct command_invocation *cmd, enum target_rese
 	}
 
 	/* We want any events to be processed before the prompt */
-	retval = target_call_timer_callbacks_now();
+	retval = target_call_timer_callbacks_now(NULL);
 
 	for (target = all_targets; target; target = target->next) {
 		target->type->check_reset(target);
@@ -1534,8 +1534,7 @@ int target_register_timer_callback(int (*callback)(void *priv),
 	(*callbacks_p)->time_ms = time_ms;
 	(*callbacks_p)->removed = false;
 
-	gettimeofday(&(*callbacks_p)->when, NULL);
-	timeval_add_time(&(*callbacks_p)->when, 0, time_ms * 1000);
+	(*callbacks_p)->when = timeval_ms() + time_ms;
 
 	(*callbacks_p)->priv = priv;
 	(*callbacks_p)->next = NULL;
@@ -1669,15 +1668,14 @@ int target_call_trace_callbacks(struct target *target, size_t len, uint8_t *data
 }
 
 static int target_timer_callback_periodic_restart(
-		struct target_timer_callback *cb, struct timeval *now)
+		struct target_timer_callback *cb, int64_t *now)
 {
-	cb->when = *now;
-	timeval_add_time(&cb->when, 0, cb->time_ms * 1000L);
+	cb->when = *now + cb->time_ms;
 	return ERROR_OK;
 }
 
 static int target_call_timer_callback(struct target_timer_callback *cb,
-		struct timeval *now)
+		int64_t *now)
 {
 	cb->callback(cb->priv);
 
@@ -1687,7 +1685,7 @@ static int target_call_timer_callback(struct target_timer_callback *cb,
 	return target_unregister_timer_callback(cb->callback, cb->priv);
 }
 
-static int target_call_timer_callbacks_check_time(int checktime)
+static int target_call_timer_callbacks_check_time(int64_t *next_event, int checktime)
 {
 	static bool callback_processing;
 
@@ -1699,8 +1697,9 @@ static int target_call_timer_callbacks_check_time(int checktime)
 
 	keep_alive();
 
-	struct timeval now;
-	gettimeofday(&now, NULL);
+	int64_t now = timeval_ms();
+	if (next_event)
+		*next_event = now + 1000;
 
 	/* Store an address of the place containing a pointer to the
 	 * next item; initially, that's a standalone "root of the
@@ -1716,11 +1715,14 @@ static int target_call_timer_callbacks_check_time(int checktime)
 
 		bool call_it = (*callback)->callback &&
 			((!checktime && (*callback)->type == TARGET_TIMER_TYPE_PERIODIC) ||
-			 timeval_compare(&now, &(*callback)->when) >= 0);
+			 now >= (*callback)->when);
 
 		if (call_it)
 			target_call_timer_callback(*callback, &now);
 
+		if (next_event && (*callback)->when < *next_event)
+			*next_event = (*callback)->when;
+
 		callback = &(*callback)->next;
 	}
 
@@ -1728,15 +1730,19 @@ static int target_call_timer_callbacks_check_time(int checktime)
 	return ERROR_OK;
 }
 
-int target_call_timer_callbacks(void)
+/**
+ * This function updates *next_event with the time (according to timeval_ms())
+ * that it would next need to be called in order to run all callbacks on time.
+ */
+int target_call_timer_callbacks(int64_t *next_event)
 {
-	return target_call_timer_callbacks_check_time(1);
+	return target_call_timer_callbacks_check_time(next_event, 1);
 }
 
 /* invoke periodic callbacks immediately */
-int target_call_timer_callbacks_now(void)
+int target_call_timer_callbacks_now(int64_t *next_event)
 {
-	return target_call_timer_callbacks_check_time(0);
+	return target_call_timer_callbacks_check_time(next_event, 0);
 }
 
 /* Prints the working area layout for debug purposes */