Res EventFlush(EventKind kind)
{
Res res;
size_t size;
AVER(eventInited);
AVER(0 <= kind && kind < EventKindLIMIT);
AVER(EventBuffer[kind] <= EventLast[kind]);
AVER(EventLast[kind] <= EventBuffer[kind] + EventBufferSIZE);
/* Is event logging enabled for this kind of event, or are or are we just
writing to the buffer for backtraces, cores, and other debugging? */
if (BS_IS_MEMBER(EventKindControl, kind)) {
size = (size_t)(EventBuffer[kind] + EventBufferSIZE - EventLast[kind]);
/* Checking the size avoids creating the event stream when the arena is
destroyed and no events have been logged. */
if (size == 0)
return ResOK;
/* Ensure the IO stream is open. We do this late so that no stream is
created if no events are enabled by telemetry control. */
if (!eventIOInited) {
res = (Res)mps_io_create(&eventIO);
if(res != ResOK)
goto failCreate;
eventIOInited = TRUE;
}
/* Writing might be faster if the size is aligned to a multiple of the
C library or kernel's buffer size. We could pad out the buffer with
a marker for this purpose. */
res = (Res)mps_io_write(eventIO, (void *)EventLast[kind], size);
if (res != ResOK)
goto failWrite;
}
res = ResOK;
failWrite:
failCreate:
/* Flush the in-memory buffer whether or not we succeeded, so that we can
record recent events there. */
EventLast[kind] = EventBuffer[kind] + EventBufferSIZE;
return res;
}
void EventSync(void)
{
EventKind kind;
Bool wrote = FALSE;
for (kind = 0; kind < EventKindLIMIT; ++kind) {
/* Is event logging enabled for this kind of event, or are or are we just
writing to the buffer for backtraces, cores, and other debugging? */
if (BS_IS_MEMBER(EventKindControl, kind)) {
size_t size;
Res res;
AVER(EventBuffer[kind] <= EventLast[kind]);
AVER(EventLast[kind] <= EventWritten[kind]);
AVER(EventWritten[kind] <= EventBuffer[kind] + EventBufferSIZE);
size = (size_t)(EventWritten[kind] - EventLast[kind]);
if (size > 0) {
/* Ensure the IO stream is open. We do this late so that no stream is
created if no events are enabled by telemetry control. */
if (!eventIOInited) {
res = (Res)mps_io_create(&eventIO);
if(res != ResOK) {
/* TODO: Consider taking some other action if open fails. */
return;
}
eventIOInited = TRUE;
}
/* Writing might be faster if the size is aligned to a multiple of the
C library or kernel's buffer size. We could pad out the buffer with
a marker for this purpose. */
res = (Res)mps_io_write(eventIO, (void *)EventLast[kind], size);
if (res == ResOK) {
/* TODO: Consider taking some other action if a write fails. */
EventWritten[kind] = EventLast[kind];
wrote = TRUE;
}
}
}
}
/* If we wrote out events, send an EventClockSync event and flush
the telemetry stream. */
if (wrote) {
(void)eventClockSync();
(void)mps_io_flush(eventIO);
}
}
