> > >>>>> "Robin" == Robin Holt <[EMAIL PROTECTED]> writes: > > Jack> Ugly hack. Isn't there a better way? (I know this isn't your > Jack> code & you probably don't like this either. I had hoped for a > Jack> cleaner solution in 2.6....) > >> It's gross, ugly and I hate it ... not sure if there's a simpler > >> way. Maybe we can use the same approach as the fbmem driver and do > >> it all in the mmap() function, I will have to investigate that. > > Robin> If you do it in the mmap, all the pages will be allocated and > Robin> mapped on the node doing the map. This will result in large > Robin> applications using multiple threads to incur _LARGE_ amounts of > Robin> numa traffic. The first fault is critical for performance. > > Robin, > > Is this because the applications will normally allocate their fetchops > in the main thread before spawning off the threads? If the mmap is > done by the thread that will 'own' the individual fetchop this > wouldn't be a problem? Sorry, just trying to understand the nature of > how these applications work, my knowledge of MPI etc. is ehm > ... limited ;)
You are correct. The parent process mmaps one segment of fetchop space and forks off all the worker processes. The worker processes inherit the fetchop mapping across the fork and each have their portion of the segment they "own". Now every process can read/write every other process' fetchop area. Dean --- Dean Roe Silicon Graphics, Inc. [EMAIL PROTECTED] - To unsubscribe from this list: send the line "unsubscribe linux-ia64" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
