I'm going to caution you about passing pointers through inproc. It may be possible to do safely, but I haven't yet figured out how to manage ownership semantics in an environment where messages (pointers) can be silently dropped.
I didn't imagine serialization would be a problem since you referred to "buffers"; I thought these would be raw byte buffers. If you actually mean lists of objects, then yes, you'll need to serialize to use inproc. There are a number of options for serialization in C++; there's Boost.Serialization, Google Protobufs, a few others. You can also do it manually if your objects are simple. Qt Signals & Slots is another solution for inter-thread communication similar to inproc which has the expected C++ object semantics and therefore doesn't require serialization. The downside is it's really only useful for one-to-one, one-to-many, or many-to-one semantics. This covers a lot, but I don't think it has a way to cover one-to-any, which is really what you want (and what the zmq push socket is designed for). On Tue, Jan 14, 2014 at 2:42 PM, Kenneth Adam Miller < [email protected]> wrote: > Yeah, it's in C/++. > > > On Tue, Jan 14, 2014 at 1:39 PM, Charles Remes <[email protected]>wrote: > >> If you are doing this from C and can access the raw memory, an inproc >> socket can pass pointers around. If you are using a managed language or one >> where accessing raw memory is difficult, you’ll want to figure out how to >> “fake” passing a pointer (or an object reference). In your case it seems >> like serializing/deserializing would be a big performance hit. That said, >> if that is the direction you must go then pick something fast like msgpack >> as your serializer. >> >> >> On Jan 14, 2014, at 1:29 PM, Kenneth Adam Miller < >> [email protected]> wrote: >> >> @AJ No, but I understand exactly why you suggested that. It's because I >> haven't explained that thread 1 is doing critical work and it needs to >> offload tasks to other threads as quickly as possible. >> >> @Lindley, Thanks so much for helping me see the truth! I was getting >> awful confused considering all the different bolony that could go on if I >> was stuck with semaphores, and I couldn't really re-envision it. Is there >> any kind of convenience function or core utility for de-serializing the >> data you receive over inproc messages? >> >> >> On Tue, Jan 14, 2014 at 12:49 PM, AJ Lewis <[email protected]> wrote: >> >>> In the zeromq example, couldn't you just skip thread 1 entirely? Then >>> the >>> PULL socket from thread 2 takes uncompressed input from the source, >>> compresses it, and shoves it out the PUSH socket to thread 3 for output. >>> >>> In this case, the PULL socket is the uncompressed pool and the PUSH >>> socket >>> is the compressed pool. Just make sure your uncompressed pool doesn't >>> fill >>> up faster than thread 2 can compress it, or you'll need to implement some >>> logic to prevent it from using up all the memory. >>> >>> AJ >>> >>> On Tue, Jan 14, 2014 at 01:16:32PM -0500, Lindley French wrote: >>> > In this case your "buffers" are really just messages, aren't they? A >>> thread >>> > grabs one (receives a message), processes it, and writes the result >>> into >>> > another buffer (sends a message). >>> > >>> > The hard part is that ZeroMQ sockets don't like to be touched by >>> multiple >>> > threads, which complicates the many-to-many pattern you have going >>> here. >>> > I'm no expert, but I would suggest.... >>> > >>> > Each "pool", A and B, becomes a single thread with two ZMQ inproc >>> sockets, >>> > one push and one pull. These are both bound to well-known endpoints. >>> All >>> > the thread does is continually shove messages from the pull socket to >>> the >>> > push socket. >>> > >>> > Each thread in "Thread set 1" has a push inproc socket connected to >>> pool >>> > A's pull socket. >>> > >>> > Each thread in "Thread set 2" has a pull inproc socket connected to >>> pool >>> > A's push socket and a push inproc socket connected to pool B's pull >>> socket. >>> > For each message it receives, it just processes it and spits it out the >>> > other socket. >>> > >>> > The thread in "Thread set 3" has a pull inproc socket connected to >>> pool B's >>> > push socket. It just continually receives messages and outputs them. >>> > >>> > This may seem complicated because concepts that were distinct before >>> > (buffer pools and worker threads) are now the same thing: they're both >>> just >>> > threads with sockets. The critical difference is that the "buffer >>> pools" >>> > bind to well-known endpoints, so you can only have a few of them, >>> while the >>> > worker threads connect to those well-known endpoints, so you can have >>> as >>> > many as you like. >>> > >>> > Will this perform as well as your current code? I don't know. Profile >>> it >>> > and find out. >>> > >>> > >>> > On Tue, Jan 14, 2014 at 12:23 PM, Kenneth Adam Miller < >>> > [email protected]> wrote: >>> > >>> > > So, I have two pools of shared buffers; pool A, which is a set of >>> buffers >>> > > of uncompressed data, and pool B, for compressed data. I three sets >>> of >>> > > threads. >>> > > >>> > > Thread set 1 pulls from pool A, and fills buffers it receives from >>> pool A >>> > > up with uncompressed data. >>> > > >>> > > Thread set 2 is given a pool from A that has recently been filled. It >>> > > pulls a buffer from pool B, compresses from A into B, and then >>> returns the >>> > > buffer it was given, cleared, back to pool A. >>> > > >>> > > Thread set 3 is a single thread, that is continually handed >>> compressed >>> > > data from thread set 2, which it outputs. When data is finished >>> output, it >>> > > returns the buffer to pool B, cleared. >>> > > >>> > > Can anybody describe a scheme to me that will allow thread sets 1 & >>> 2 to >>> > > scale? >>> > > >>> > > Also, suppose for pools A and B, I'm using shared queues that are >>> just C++ >>> > > stl lists. When I pop from the front, I use a lock for removal to >>> make sure >>> > > that removal is deterministic. When I enqueue, I use a separate lock >>> to >>> > > ensure that the internals of the STL list is respected (don't want >>> two >>> > > threads receiving iterators to the same beginning node, that would >>> probably >>> > > corrupt the container or cause data loss, or both). Is this the >>> appropriate >>> > > way to go about it? Thread sets 1 & 2 will likely have more than one >>> > > thread, but there's no guarantee that thread sets 1 & 2 will have >>> equal >>> > > threads. >>> > > >>> > > I was reading the ZeroMQ manual, and I read the part about >>> multi-threading >>> > > and message passing, and I was wondering what approaches should be >>> taken >>> > > with message passing when data is inherently shared between threads. >>> > > >>> > > _______________________________________________ >>> > > zeromq-dev mailing list >>> > > [email protected] >>> > > http://lists.zeromq.org/mailman/listinfo/zeromq-dev >>> > > >>> > > >>> >>> > _______________________________________________ >>> > zeromq-dev mailing list >>> > [email protected] >>> > http://lists.zeromq.org/mailman/listinfo/zeromq-dev >>> >>> >>> -- >>> AJ Lewis >>> Software Engineer >>> Quantum Corporation >>> >>> Work: 651 688-4346 >>> email: [email protected] >>> >>> ---------------------------------------------------------------------- >>> The information contained in this transmission may be confidential. Any >>> disclosure, copying, or further distribution of confidential information is >>> not permitted unless such privilege is explicitly granted in writing by >>> Quantum. Quantum reserves the right to have electronic communications, >>> including email and attachments, sent across its networks filtered through >>> anti virus and spam software programs and retain such messages in order to >>> comply with applicable data security and retention requirements. Quantum is >>> not responsible for the proper and complete transmission of the substance >>> of this communication or for any delay in its receipt. >>> _______________________________________________ >>> zeromq-dev mailing list >>> [email protected] >>> http://lists.zeromq.org/mailman/listinfo/zeromq-dev >>> >> >> _______________________________________________ >> zeromq-dev mailing list >> [email protected] >> http://lists.zeromq.org/mailman/listinfo/zeromq-dev >> >> >> >> _______________________________________________ >> zeromq-dev mailing list >> [email protected] >> http://lists.zeromq.org/mailman/listinfo/zeromq-dev >> >> > > _______________________________________________ > zeromq-dev mailing list > [email protected] > http://lists.zeromq.org/mailman/listinfo/zeromq-dev > >
_______________________________________________ zeromq-dev mailing list [email protected] http://lists.zeromq.org/mailman/listinfo/zeromq-dev
