Hello, Jeff Squyres, le Thu 11 Mar 2010 17:34:59 -0800, a écrit : > On Mar 11, 2010, at 3:57 PM, Samuel Thibault wrote: > > > > What *is* hwloc's policy about thread safety, anyway? > > > > It would be odd to not be threadsafe, considering the target > > applications :) and I believe hwloc is already. > > Hmm. I'm not so sure. Consider: > > 1. thread A calls hwloc_topology_init(&a) > 2. thread A calls hwloc_topology_load(a) > 3. thread A launches thread B > 4. thread B calls hwloc_topology_get_*(a...) > 5. thread A calls hwloc_topology_load(a)
Well, yes, of course :) I mean "thread-safe" like libc is thread-safe: if you call functions that modify a buffer concurrently, you're hosed :) But all the reading functions, or working on separate topology objects are fine to run in parallel. > It depends on exactly what you mean by "thread safe" (kinda like MPI's 4 > different levels of thread support). It's between THREAD_MULTIPLE (for read operations) and THREAD_SERIALIZE (for write operations on the same object). That being said, we could easily add a mutex which we take in write operations to become completely THREAD_MULTIPLE-safe, as there aren't so many write operations. Samuel
