On Thu, 17 Mar 2005, Andrew Morton wrote: > > http://oss.sgi.com/projects/page_fault_performance/ > > Oh no, not that page again ;)
Yes indeed! > Seems to say that prezeroing makes negligible difference to kernel builds, > but speeds up a big malloc+memset by 3x to 4x, yes? Correct. > Are there any real-worldish workloads which show an appreciable benefit? Ummm. Big loads are our real-worldish workloads here. > The large speedup for a big memset seems odd - I assume it's simply > transferring CPU load from the user's process over to kscrubd. Or is it > the fancy page-zeroing hardware? How do we differentiate the two? I switched off the page-zeroing hardware for the tests. > Are there any workloads which are seeing a benefit on a CPU which doesn't > have the zeroing hardware? Without zeroing hardware the eroing actions are moved to idle system time (load < /proc/sys/vm/scrub_load). Its shifting the cpu load. But I just fixed things up so that the kernel can return hot zeroed pages to the pool for quicklist management. This yields zeroed pages without kscrubd. - 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/
