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-rw-r--r--docs/users_guide/8.10.1-notes.rst4
-rw-r--r--docs/users_guide/runtime_control.rst22
-rw-r--r--includes/rts/EventLogWriter.h28
-rw-r--r--rts/Trace.c29
-rw-r--r--rts/eventlog/EventLog.c100
-rw-r--r--rts/eventlog/EventLog.h6
-rw-r--r--rts/eventlog/EventLogWriter.c1
-rw-r--r--testsuite/tests/rts/InitEventLogging.hs11
-rw-r--r--testsuite/tests/rts/InitEventLogging.stdout8
-rw-r--r--testsuite/tests/rts/InitEventLogging_c.c33
-rw-r--r--testsuite/tests/rts/all.T3
11 files changed, 195 insertions, 50 deletions
diff --git a/docs/users_guide/8.10.1-notes.rst b/docs/users_guide/8.10.1-notes.rst
index d9b48d95e0..e5ed23ca3e 100644
--- a/docs/users_guide/8.10.1-notes.rst
+++ b/docs/users_guide/8.10.1-notes.rst
@@ -222,6 +222,10 @@ Runtime system
out-of-the-box compatibility with OpenBSD and macOS Catalina (see
:ghc-ticket:`17353`)
+- The RTS API now exposes :ref:`an interface <event_log_output_api>` to
+ configure ``EventLogWriters``, allowing eventlog data to fed to sinks other
+ than ``.eventlog`` files.
+
Template Haskell
~~~~~~~~~~~~~~~~
diff --git a/docs/users_guide/runtime_control.rst b/docs/users_guide/runtime_control.rst
index 7ebb9eb207..1f4b766400 100644
--- a/docs/users_guide/runtime_control.rst
+++ b/docs/users_guide/runtime_control.rst
@@ -174,6 +174,8 @@ e.g., on stack overflow. The hooks for these are as follows:
The message printed if ``malloc`` fails.
+.. _event_log_output_api:
+
Event log output
################
@@ -190,7 +192,7 @@ Furthermore GHC lets you specify the way event log data (see :rts-flag:`-l
.. c:member:: bool writeEventLog(void *eventlog, size_t eventlog_size)
- Hands buffered event log data to your event log writer.
+ Hands buffered event log data to your event log writer. Return true on success.
Required for a custom :c:type:`EventLogWriter`.
.. c:member:: void flushEventLog(void)
@@ -202,6 +204,24 @@ Furthermore GHC lets you specify the way event log data (see :rts-flag:`-l
Called when event logging is about to stop. This can be ``NULL``.
+To use an :c:type:`EventLogWriter` the RTS API provides the following functions:
+
+.. c:func:: enum EventLogStatus eventLogStatus(void)
+
+ Query whether the current runtime system supports the eventlog (e.g. whether
+ the current executable was linked with :ghc-flag:`-eventlog`) and, if it
+ is supported, whether it is currently logging.
+
+.. c:func:: bool startEventLogging(const EventLogWriter *writer)
+
+ Start logging events to the given :c:type:`EventLogWriter`. Returns true on
+ success or false is another writer has already been configured.
+
+.. c:func:: void endEventLogging()
+
+ Tear down the active :c:type:`EventLogWriter`.
+
+
.. _rts-options-misc:
Miscellaneous RTS options
diff --git a/includes/rts/EventLogWriter.h b/includes/rts/EventLogWriter.h
index 5eececd20e..4975b72b07 100644
--- a/includes/rts/EventLogWriter.h
+++ b/includes/rts/EventLogWriter.h
@@ -23,7 +23,7 @@ typedef struct {
// Initialize an EventLogWriter (may be NULL)
void (* initEventLogWriter) (void);
- // Write a series of events
+ // Write a series of events returning true on success.
bool (* writeEventLog) (void *eventlog, size_t eventlog_size);
// Flush possibly existing buffers (may be NULL)
@@ -38,3 +38,29 @@ typedef struct {
* a file `program.eventlog`.
*/
extern const EventLogWriter FileEventLogWriter;
+
+enum EventLogStatus {
+ /* The runtime system wasn't compiled with eventlog support. */
+ EVENTLOG_NOT_SUPPORTED,
+ /* An EventLogWriter has not yet been configured */
+ EVENTLOG_NOT_CONFIGURED,
+ /* An EventLogWriter has been configured and is running. */
+ EVENTLOG_RUNNING,
+};
+
+/*
+ * Query whether the current runtime system supports eventlogging.
+ */
+enum EventLogStatus eventLogStatus(void);
+
+/*
+ * Initialize event logging using the given EventLogWriter.
+ * Returns true on success or false if an EventLogWriter is already configured
+ * or eventlogging isn't supported by the runtime.
+ */
+bool startEventLogging(const EventLogWriter *writer);
+
+/*
+ * Stop event logging and destroy the current EventLogWriter.
+ */
+void endEventLogging(void);
diff --git a/rts/Trace.c b/rts/Trace.c
index 8e44716eb0..b35be3c1e7 100644
--- a/rts/Trace.c
+++ b/rts/Trace.c
@@ -40,21 +40,12 @@ int TRACE_cap;
static Mutex trace_utx;
#endif
-static bool eventlog_enabled;
-
/* ---------------------------------------------------------------------------
Starting up / shutting down the tracing facilities
--------------------------------------------------------------------------- */
-static const EventLogWriter *getEventLogWriter(void)
-{
- return rtsConfig.eventlog_writer;
-}
-
void initTracing (void)
{
- const EventLogWriter *eventlog_writer = getEventLogWriter();
-
#if defined(THREADED_RTS)
initMutex(&trace_utx);
#endif
@@ -95,15 +86,14 @@ void initTracing (void)
TRACE_spark_full ||
TRACE_user;
- eventlog_enabled = RtsFlags.TraceFlags.tracing == TRACE_EVENTLOG &&
- eventlog_writer != NULL;
-
/* Note: we can have any of the TRACE_* flags turned on even when
eventlog_enabled is off. In the DEBUG way we may be tracing to stderr.
*/
+ initEventLogging();
- if (eventlog_enabled) {
- initEventLogging(eventlog_writer);
+ if (RtsFlags.TraceFlags.tracing == TRACE_EVENTLOG
+ && rtsConfig.eventlog_writer != NULL) {
+ startEventLogging(rtsConfig.eventlog_writer);
}
}
@@ -121,17 +111,10 @@ void freeTracing (void)
}
}
+// Used to reset tracing in a forked child
void resetTracing (void)
{
- const EventLogWriter *eventlog_writer;
- eventlog_writer = getEventLogWriter();
-
- if (eventlog_enabled) {
- abortEventLogging(); // abort eventlog inherited from parent
- if (eventlog_writer != NULL) {
- initEventLogging(eventlog_writer); // child starts its own eventlog
- }
- }
+ restartEventLogging();
}
void flushTrace (void)
diff --git a/rts/eventlog/EventLog.c b/rts/eventlog/EventLog.c
index 5f22af5bfc..e3597cd73c 100644
--- a/rts/eventlog/EventLog.c
+++ b/rts/eventlog/EventLog.c
@@ -26,7 +26,9 @@
#include <unistd.h>
#endif
-static const EventLogWriter *event_log_writer;
+bool eventlog_enabled;
+
+static const EventLogWriter *event_log_writer = NULL;
#define EVENT_LOG_SIZE 2 * (1024 * 1024) // 2MB
@@ -516,16 +518,22 @@ postHeaderEvents(void)
postInt32(&eventBuf, EVENT_DATA_BEGIN);
}
-void
-initEventLogging(const EventLogWriter *ev_writer)
+static uint32_t
+get_n_capabilities(void)
{
- uint32_t n_caps;
+#if defined(THREADED_RTS)
+ // XXX n_capabilities may not have been initialized yet
+ return (n_capabilities != 0) ? n_capabilities : RtsFlags.ParFlags.nCapabilities;
+#else
+ return 1;
+#endif
+}
+void
+initEventLogging()
+{
init_event_types();
- event_log_writer = ev_writer;
- initEventLogWriter();
-
int num_descs = sizeof(EventDesc) / sizeof(char*);
if (num_descs != NUM_GHC_EVENT_TAGS) {
barf("EventDesc array has the wrong number of elements (%d, NUM_GHC_EVENT_TAGS=%d)",
@@ -542,18 +550,28 @@ initEventLogging(const EventLogWriter *ev_writer)
* Use a single buffer to store the header with event types, then flush
* the buffer so all buffers are empty for writing events.
*/
-#if defined(THREADED_RTS)
- // XXX n_capabilities hasn't been initialized yet
- n_caps = RtsFlags.ParFlags.nCapabilities;
-#else
- n_caps = 1;
-#endif
- moreCapEventBufs(0, n_caps);
+ moreCapEventBufs(0, get_n_capabilities());
initEventsBuf(&eventBuf, EVENT_LOG_SIZE, (EventCapNo)(-1));
#if defined(THREADED_RTS)
initMutex(&eventBufMutex);
#endif
+}
+
+enum EventLogStatus
+eventLogStatus(void)
+{
+ if (eventlog_enabled) {
+ return EVENTLOG_RUNNING;
+ } else {
+ return EVENTLOG_NOT_CONFIGURED;
+ }
+}
+
+static bool
+startEventLogging_(void)
+{
+ initEventLogWriter();
postHeaderEvents();
@@ -564,14 +582,42 @@ initEventLogging(const EventLogWriter *ev_writer)
*/
printAndClearEventBuf(&eventBuf);
- for (uint32_t c = 0; c < n_caps; ++c) {
+ for (uint32_t c = 0; c < get_n_capabilities(); ++c) {
postBlockMarker(&capEventBuf[c]);
}
+ return true;
+}
+
+bool
+startEventLogging(const EventLogWriter *ev_writer)
+{
+ if (eventlog_enabled || event_log_writer) {
+ return false;
+ }
+
+ eventlog_enabled = true;
+ event_log_writer = ev_writer;
+ return startEventLogging_();
+}
+
+// Called during forkProcess in the child to restart the eventlog writer.
+void
+restartEventLogging(void)
+{
+ freeEventLogging();
+ stopEventLogWriter();
+ initEventLogging(); // allocate new per-capability buffers
+ if (event_log_writer != NULL) {
+ startEventLogging_(); // child starts its own eventlog
+ }
}
void
endEventLogging(void)
{
+ if (!eventlog_enabled)
+ return;
+
// Flush all events remaining in the buffers.
for (uint32_t c = 0; c < n_capabilities; ++c) {
printAndClearEventBuf(&capEventBuf[c]);
@@ -586,6 +632,8 @@ endEventLogging(void)
printAndClearEventBuf(&eventBuf);
stopEventLogWriter();
+ event_log_writer = NULL;
+ eventlog_enabled = false;
}
void
@@ -626,13 +674,6 @@ freeEventLogging(void)
}
}
-void
-abortEventLogging(void)
-{
- freeEventLogging();
- stopEventLogWriter();
-}
-
/*
* Post an event message to the capability's eventlog buffer.
* If the buffer is full, prints out the buffer and clears it.
@@ -1440,7 +1481,7 @@ void printAndClearEventBuf (EventsBuf *ebuf)
size_t elog_size = ebuf->pos - ebuf->begin;
if (!writeEventLog(ebuf->begin, elog_size)) {
debugBelch(
- "printAndClearEventLog: could not flush event log"
+ "printAndClearEventLog: could not flush event log\n"
);
resetEventsBuf(ebuf);
return;
@@ -1524,4 +1565,17 @@ void postEventType(EventsBuf *eb, EventType *et)
postInt32(eb, EVENT_ET_END);
}
+#else
+
+enum EventLogStatus eventLogStatus(void)
+{
+ return EVENTLOG_NOT_SUPPORTED;
+}
+
+bool startEventLogging(const EventLogWriter *writer STG_UNUSED) {
+ return false;
+}
+
+void endEventLogging(void) {}
+
#endif /* TRACING */
diff --git a/rts/eventlog/EventLog.h b/rts/eventlog/EventLog.h
index 5bd3b5dadb..eca76619cd 100644
--- a/rts/eventlog/EventLog.h
+++ b/rts/eventlog/EventLog.h
@@ -22,8 +22,10 @@
*/
extern char *EventTagDesc[];
-void initEventLogging(const EventLogWriter *writer);
-void endEventLogging(void);
+extern bool eventlog_enabled;
+
+void initEventLogging(void);
+void restartEventLogging(void);
void freeEventLogging(void);
void abortEventLogging(void); // #4512 - after fork child needs to abort
void flushEventLog(void); // event log inherited from parent
diff --git a/rts/eventlog/EventLogWriter.c b/rts/eventlog/EventLogWriter.c
index 4b486926a7..b19e617a4c 100644
--- a/rts/eventlog/EventLogWriter.c
+++ b/rts/eventlog/EventLogWriter.c
@@ -122,6 +122,7 @@ stopEventLogFileWriter(void)
{
if (event_log_file != NULL) {
fclose(event_log_file);
+ event_log_file = NULL;
}
}
diff --git a/testsuite/tests/rts/InitEventLogging.hs b/testsuite/tests/rts/InitEventLogging.hs
new file mode 100644
index 0000000000..1ec1e65028
--- /dev/null
+++ b/testsuite/tests/rts/InitEventLogging.hs
@@ -0,0 +1,11 @@
+{-# LANGUAGE ForeignFunctionInterface #-}
+
+-- Test that the startEventLog interface works as expected.
+main :: IO ()
+main = do
+ putStrLn "Starting eventlog..."
+ c_init_eventlog
+ putStrLn "done"
+
+foreign import ccall unsafe "init_eventlog"
+ c_init_eventlog :: IO ()
diff --git a/testsuite/tests/rts/InitEventLogging.stdout b/testsuite/tests/rts/InitEventLogging.stdout
new file mode 100644
index 0000000000..7cbab8fe59
--- /dev/null
+++ b/testsuite/tests/rts/InitEventLogging.stdout
@@ -0,0 +1,8 @@
+Starting eventlog...
+done
+init
+write
+write
+write
+write
+stop
diff --git a/testsuite/tests/rts/InitEventLogging_c.c b/testsuite/tests/rts/InitEventLogging_c.c
new file mode 100644
index 0000000000..47e4520fc4
--- /dev/null
+++ b/testsuite/tests/rts/InitEventLogging_c.c
@@ -0,0 +1,33 @@
+#include <stdio.h>
+#include <Rts.h>
+
+void test_init(void) {
+ printf("init\n");
+}
+
+bool test_write(void *eventlog, size_t eventlog_size) {
+ printf("write\n");
+ return true;
+}
+
+void test_flush(void) {
+ printf("flush\n");
+}
+
+void test_stop(void) {
+ printf("stop\n");
+}
+
+const EventLogWriter writer = {
+ .initEventLogWriter = test_init,
+ .writeEventLog = test_write,
+ .flushEventLog = test_flush,
+ .stopEventLogWriter = test_stop
+};
+
+void init_eventlog(void) {
+ if (!startEventLogging(&writer)) {
+ printf("failed to start eventlog\n");
+ }
+}
+
diff --git a/testsuite/tests/rts/all.T b/testsuite/tests/rts/all.T
index bd634d1e56..0bbddfba3e 100644
--- a/testsuite/tests/rts/all.T
+++ b/testsuite/tests/rts/all.T
@@ -406,3 +406,6 @@ test('T13676',
[when(opsys('darwin') or opsys('mingw32'), expect_broken(17447)),
extra_files(['T13676.hs'])],
ghci_script, ['T13676.script'])
+test('InitEventLogging',
+ [only_ways(['normal']), extra_run_opts('+RTS -RTS')],
+ compile_and_run, ['-eventlog InitEventLogging_c.c'])
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