Well, I'm just a type safety dork, so I tend to think that even losing type information over one pointer, even if I know where that pointer is going to end up what type it represents on the other side, is a bad thing. Plus it's a performance thing that's just unnecessary, but I don't think it's a big deal. These aren't objects, they are indeed raw buffers, as you assumed.
Also, awesome about the boost find! Appreciate you so much, you are a beast. But I'm actually still in a sprint, so there's no version or commit with which these hypothetical discussions directly coincide, you're helping me get it right the first time. On Tue, Jan 14, 2014 at 2:48 PM, Lindley French <[email protected]> wrote: > A visit to the Boost libraries reveals there's a brand-new Boost.Lockfree > library that must have arrived with one of the last few versions. You > should seriously consider simply replacing your std::lists with > boost::lockfree::queues using your existing logic, and see if that gives > you the performance you're looking for before you make any massive changes. > > > On Tue, Jan 14, 2014 at 3:40 PM, Lindley French <[email protected]>wrote: > >> 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 > >
_______________________________________________ zeromq-dev mailing list [email protected] http://lists.zeromq.org/mailman/listinfo/zeromq-dev
