On 02/02/2012 12:21 PM, Takuya Yoshikawa wrote: > (2012/02/02 19:10), Avi Kivity wrote: > >>> >>> ========================================================= >>> # of dirty pages: kvm.git (ns), with this patch (ns) >>> 1: 102,077 ns 10,105 ns >>> 2: 47,197 ns 9,395 ns >>> 4: 43,563 ns 9,938 ns >>> 8: 41,239 ns 10,618 ns >>> 16: 42,988 ns 12,299 ns >>> 32: 45,503 ns 14,298 ns >>> 64: 50,915 ns 19,895 ns >>> 128: 61,087 ns 29,260 ns >>> 256: 81,007 ns 49,023 ns >>> 512: 132,776 ns 86,670 ns >>> 1024: 939,299 ns 131,496 ns >>> 2048: 992,209 ns 250,429 ns >>> 4096: 891,809 ns 479,280 ns >>> 8192: 1,027,280 ns 906,971 ns >>> (until now pretty good) >>> >>> (ah, for every 32-bit atomic clear mask ...) >>> 16384: 1,270,972 ns 6,661,741 ns // 1 1 1 ... 1 >>> 32768: 1,581,335 ns 9,673,985 ns // ... >>> 65536: 2,161,604 ns 11,466,134 ns // ... >>> 131072: 3,253,027 ns 13,412,954 ns // ... >>> 262144: 5,663,002 ns 16,309,924 ns // 31 31 31 ... 31 >>> ========================================================= >> >> On a 64-bit host, this will be twice as fast. Or if we use cmpxchg16b, >> and there are no surprises, four times as fast. It will still be slower >> than the original, but by a smaller margin. > > Yes. > > I used "unsigned int" just because I wanted to use the current > atomic_clear_mask() as is. > > We need to implement atomic_clear_mask_long() or use ... If we use cmpxchg8b/cmpxchg16b then this won't fit with the atomic_*_long family. -- error compiling committee.c: too many arguments to function -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
