> From: zfs-discuss-boun...@opensolaris.org [mailto:zfs-discuss- > boun...@opensolaris.org] On Behalf Of Peter Jeremy > > My interpretation of those results is that you can't generalise: The > only way to determine whether your application is faster in 32-bit or > 64-bit more is to test it. And your choice of algorithm is at least > as important as whether it's 32-bit or 64-bit.
Not just your choice of algorithm, but architecture. Consider the dramatic architecture difference between Intel and AMD. Though they may have the same instruction set (within reason) the internal circuits to process those instructions are dramatically different, and hence, performance is dramatically different. Intel might be 4x faster at some instruction, while AMD is 4x faster at some other instruction. The same dramatic difference is present for 32 vs 64. As soon as you change modes of your CPU, the architecture of the chip might as well be totally different. If you want to optimize performance, you have to first be able to classify your work load. If you cannot create a job which is truly typical of your work load, all bets are off. Don't even bother. For general computing, the more you spend, the faster it goes. Only if you have some task which will be repeated for long periods of time ... Then you can benefit by trying this CPU, or that CPU, or this mode, or that mode, or this chipset, or tweaking the compile flags, etc. If you have one task which is faster 32bit, it's not representative of 32 vs 64 in general. And vice-versa. _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
