On Mon, 28 Mar 2005, Chen, Kenneth W wrote: > With that said, here goes our first data point along with some historical data > we have collected so far. > > 2.6.11 -13% > 2.6.9 - 6% > 2.6.8 -23% > 2.6.2 - 1% > baseline (rhel3)
Linus Torvalds wrote on Tuesday, March 29, 2005 4:00 PM > How repeatable are the numbers across reboots with the same kernel? Some > benchmarks will depend heavily on just where things land in memory, > especially with things like PAE or even just cache behaviour (ie if some > frequenly-used page needs to be kmap'ped or not depending on where it > landed). Very repeatable. This workload is very steady and resolution in throughput is repeatable down to 0.1%. We toss everything below that level as noise. > You don't have the PAE issue on ia64, but there could be other issues. > Some of them just disk-layout issues or similar, ie performance might > change depending on where on the disk the data is written in relationship > to where most of the reads come from etc etc. The fact that it seems to > fluctuate pretty wildly makes me wonder how stable the numbers are. This workload has been around for 10+ years and people at Intel studied the characteristics of this workload inside out for 10+ years. Every stones will be turned at least more than once while we tune the entire setup making sure everything is well balanced. And we tune the system whenever there is a hardware change. Data layout on the disk spindle are very well balanced. > Also, it would be absolutely wonderful to see a finer granularity (which > would likely also answer the stability question of the numbers). If you > can do this with the daily snapshots, that would be great. If it's not > easily automatable, or if a run takes a long time, maybe every other or > every third day would be possible? I sure will make my management know that Linus wants to see the performance number on a daily bases (I will ask for a couple of million dollar to my manager for this project :-)) - 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/
