The boot-time migration cost auto-tuning stuff seems to have been merged to Linus' tree since 2.6.15. On little one- or two-processor systems, the time required to measure the migration costs isn't very noticeable, but by the time we get to even a four-processor ia64 box, it adds about 30 seconds to the boot time, which seems like a lot. Is that expected? Is the information we get really worth that much? Could the measurement be done at run-time instead? Is there a smaller hammer we could use, e.g., flushing just the buffer rather than the *entire* cache? Did we just implement sched_cacheflush() incorrectly for ia64? Only ia64, x86, and x86_64 currently have a non-empty sched_cacheflush(), and the x86* ones contain only "wbinvd()". So I suspect that only ia64 sees this slowdown. But I would guess that other arches will implement it in the future. Bjorn - To unsubscribe from this list: send the line "unsubscribe linux-ia64" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.htmlReceived on Sat Jan 28 08:04:13 2006
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