On Fri, Dec 27, 2013 at 06:32:24PM +0800, Gu Zheng wrote: > Hi Matthew, > On 12/26/2013 10:13 PM, Matthew Wilcox wrote: > > > On Thu, Dec 26, 2013 at 06:22:10PM +0800, Gu Zheng wrote: > >> to the new free slot if it's smaller than 'next_free'. So that we can > >> ensure that the slots before 'next_free' are all used, and the search can start > >> from 'next_free' to reduce the search and improve the performance. > > > > Have you benchmarked it? What kinds of improvements are you seeing? > > Not yet. But the improvement is obvious, we can always reduce the search region and > improve the hit rate when trying to find a free slot with this change. It's not so obvious to me. You've added extra stores, which may dirty an additional cacheline. That may end up costing more than it saves. I suspect the difference is lost in the noise, but I've been wrong about these things before. -- Matthew Wilcox Intel Open Source Technology Centre "Bill, look, we understand that you're interested in selling us this operating system, but compare it to ours. We can't possibly take such a retrograde step." -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
