On Monday 14 January 2008 22:30, Andi Kleen wrote: > In general there are more scaling problems like this (e.g. it also doesn't > make sense to scale kernel threads for each CPU thread for example).
I think in a lot of ways, per-CPU kernel threads scale OK. At least they should mostly be dynamic, so they don't require overhead on smaller systems. On larger systems, I don't know if there are too many kernel problems with all those threads (except for userspace tools sometimes don't report well). And I think making them per-CPU can be much easier than tuning some arbitrary algorithm to get a mix between parallelism and footprint. For example, I'm finding that it might actually be worthwhile to move some per-node and dynamically-controlled thread creation over to the basic per-CPU scheme because of differences in topologies... Anyway, that's just an aside. Oh, just while I remember it also, something funny is that MAX_NUMNODES can be bigger than NR_CPUS on x86. I guess one can have CPUless nodes, but wouldn't it make sense to have an upper bound of NR_CPUS by default? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/