On Sat, Jun 9, 2012 at 1:34 AM, Mikhail Eremin <meremin@gmail.com> wrote:
Hello, SETTING: - There is an application, written using Boost Template library, meant for QUICK processing of bulk text files (cca 50-100Gb each). - There is a huge, quick and expensive piece of hardware with HUGE amount of RAM and multiple CPU. - There is [theoretically] any possible UNIX-like OS, even Microsoft Windows(R) is considered. - Boost Thread Pool extension is used; previously memory mapped files through memory_segment have been used, now got rid of the entire Boost::interprocess. - There are NO explicit data items in the application's algorithm to be shared by threads, each has its own piece of input file, thus - there is NO explicit concurrency. PROBLEM: - Ensure fast processing without locks and threads sleeping. Currently the threads sleep on some internal mutex. We thought it's been boost::interprocess (specifically - mmap, wrapped by a mutex), but it apparently isn't so.
SPECIFIC QUESTION: - How could we get rid of Boost locks?
Mike
Okay, so you have enough memory to map an entire file into memory at once? Are the files read-only? Where are you using a boost lock to get rid of? Probably the threadpool library uses a lock on a queue somewhere? You could certainly write this without a threadpool. I'd imagine that the cost of launching threads will be insignificant compared to running the algorithm on these regions: std::vector< std::pair<uint64_t, uint64_t> > regions; boost::atomic<size_t> nextRegion; struct RegionThread { /*mmap info variables*/ RegionThread(/*mmap info*/) : /*mmapinfo member(mmap info) */{} void operator() () { while(true) { size_t next = nextRegion.fetch_add(1); if(next >= regions.size()) { break; } std::pair<uint64_t, uint64_t> const ®ion = regions[next]; /*perform algorithm on region of mmapped file...*/ } } }; void operateOnFile(/*some mmap info*/) { regions.clear(); // set up regions for this file nextRegion boost::thread_group tg; for(size_t i = 0; i < boost::thread::hardware_concurrency(); ++i) { tg.create_thread(RegionThread(/*mmap info*/)); } tg.join_all(); } If you can statically schedule the work into sets of regions that each thread will work on, this is even easier, and can be done without even an atomic variable. Brian