| Commit message (Collapse) | Author | Age |
|---|
| ... | |
| |
|
|
|
|
|
|
|
|
|
|
|
|
| |
We allocate AIO structures dynamically, so that we can use them
abstractly in more places without inlining them. This will be used
for the ZeroTier transport to allow us to create operations consisting
of just the AIO. Furthermore, we provide accessors for some of the
aio members, in the hopes that we will be able to wrap these for
"safe" version of the AIO capability to export to applications, and
to protocol and transport implementors.
While here we cleaned up the protocol details to use consistently
shorter names (no nni_ prefix for static symbols needed), and we
also fixed a bug in the surveyor code.
|
| |
|
|
|
|
|
|
|
| |
This moves the DNS related functionality into common code, and also
removes all the URL parsing stuff out of the platform specific code
and into the transports. Now the transports just take sockaddr's on
initialization. (We may want to move this until later.)
We also add UDP resolution as another separate API.
|
| |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| |
If the underlying platform fails (FreeBSD is the only one I'm aware
of that does this!), we use a global lock or condition variable instead.
This means that our lock initializers never ever fail.
Probably we could eliminate most of this for Linux and Darwin, since
on those platforms, mutex and condvar initialization reasonably never
fails. Initial benchmarks show little difference either way -- so we
can revisit (optimize) later.
This removes a lot of otherwise untested code in error cases and so forth,
improving coverage and resilience in the face of allocation failures.
Platforms other than POSIX should follow a similar pattern if they need
this. (VxWorks, I'm thinking of you.) Most sane platforms won't have
an issue here, since normally these initializations do not need to allocate
memory. (Reportedly, even FreeBSD has plans to "fix" this in libthr2.)
While here, some bugs were fixed in initialization & teardown.
The fallback code is properly tested with dedicated test cases.
|
| |
|
|
|
|
|
|
|
|
|
|
|
|
| |
A little benchmarking showed that we were encountering far too many
wakeups, leading to severe performance degradation; we had a bunch
of threads all sleeping on the same condition variable (taskqs)
and this woke them all up, resulting in heavy mutex contention.
Since we only need one of the threads to wake, and we don't care which
one, let's just wake only one. This reduced RTT latency from about
240 us down to about 30 s. (1/8 of the former cost.)
There's still a bunch of tuning to do; performance remains worse than
we would like.
|
| |
|
|
|
|
|
|
|
| |
This passes valgrind 100% clean for both helgrind and deep leak
checks. This represents a complete rethink of how the AIOs work,
and much simpler synchronization; the provider API is a bit simpler
to boot, as a number of failure modes have been simply eliminated.
While here a few other minor bugs were squashed.
|
| |
|
|
| |
block for any AIO completion.
|
| |
|
|
|
|
|
| |
The queue is bound at initialization time of the task, and we call
entries just tasks, so we don't have to pass around a taskq pointer
across all the calls. Further, nni_task_dispatch is now guaranteed
to succeed.
|
| |
|
|
|
|
|
|
|
| |
We need to remember that protocol stops can run synchronously, and
therefore we need to wait for the aio to complete. Further, we need
to break apart shutting down aio activity from deallocation, as we need
to shut down *all* async activity before deallocating *anything*.
Noticed that we had a pipe race in the surveyor pattern too.
|
| |
|
|
|
|
| |
Apparently there are circumstances when a pipedesc may get orphaned form the
pollq. This triggers an assertion failure when it occurs. I am still
trying to understand how this can occur. Stay tuned.
|
| |
|
|
|
|
|
|
|
|
|
| |
We have seen leaks of pipes causing test failures (e.g. the Windows
IPC test) due to EADDRINUSE. This was caused by a case where we
failed to pass the pipe up because the AIO had already been canceled,
and we didn't realize that we had oprhaned the pipe. The fix is to
add a return value to nni_aio_finish, and verify that we did finish
properly, or if we did not then we must free the pipe ourself. (The
zero return from nni_aio_finish indicates that it accepts ownership
of resources passed via the aio.)
|
| |
|
|
|
|
|
|
| |
We closed a few subtle races in the AIO subsystem as well, and now
we were able to eliminate the separate timer handling the MQ code.
There appear to be some opportunities to further enhance the code
for MQs as well -- eventually probably the only access to MQs will
be with AIOs.
|
| | |
|
| | |
|
| | |
|
| | |
|
| | |
|
| | |
|
| | |
|
| |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| |
This eliminates the two threads per pipe that were being used to provide
basic I/O handling, replacing them with a single global thread for now,
that uses poll and nonblocking I/O. This should lead to great scalability.
The infrastructure is in place to easily expand to multiple polling worker
threads. Some thought needs to be given about how to scale this to engage
multiple CPUs. Horizontal scaling may also shorten the poll() lists easing
C10K problem.
We should look into better solutions than poll() for platforms that have
them (epoll on Linux, kqueue on BSD, and event ports on illumos).
Note that the file descriptors start out in blocking mode for now, but
then are placed into non-blocking mode. This is because the negotiation
phase is not yet callback driven, and so needs to be synchronous.
|
| |
|
|
|
|
|
| |
Transport-level pipe initialization is now sepearate and explicit.
The POSIX send/recv logic still uses threads under the hood, but
makes use of the AIO framework for send/recv. This is a key stepping
stone towards enabling poll() or similar async I/O approaches.
|
| | |
|
| | |
|
| | |
|
| | |
|
|
|
We will still need some kind of specific handling of cancellation for
msg queues, but it will be simpler to just implement that for the queues,
and not worry about cancellation in the general case around poll etc.
(The low level poll and I/O routines will get notified by their underlying
transport pipes/descriptors closing.)
|
