Messages in this thread | | | Date | Sun, 29 Nov 1998 13:05:56 -0500 (EST) | From | Gregory Maxwell <> | Subject | RE: SMP scalability: 8 -> 32 CPUs |
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Well.. The question was of Linux's SMP scalability in general, not just running a single app.. When running multiple differnt apps your bottlenecks are serialization in the kernel, and IO.
On Sat, 28 Nov 1998, Richard Solis wrote:
> For a good overview of the challenges associated with getting good > performance out of multiple processors (SMPs and clusters), see "In Search > of Clusters" by Gregory F. Pfister. I bought it a year ago when the first > edition hit and then later got the second edition. It's a good book written > by a guy who worked at IBM's Watson Research Facility. > > It turns out that neither memory or I/O is the real reason that you can't > get good performance from multiple processors. It's the programs! Some > problems are hard to solve in anything but a serial fashion so adding > processors doesn't help. Some programs (like databases) access certain > portions of data frequently, so you have collisions between the processors > all trying to access the same data, etc. There are whole buckets of > reasons. They basically fall into serialization, memory coherence, and > overhead (granularity) associated with propogating updates to data shared by > multiple processors.
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