On thu, 24 Mar 2011 08:29:57 +0100, Arne Jansen wrote: > On 24.03.2011 02:38, Miao Xie wrote: >> On wed, 23 Mar 2011 21:28:25 +0100, Arne Jansen wrote: >>> On 23.03.2011 20:26, Andrey Kuzmin wrote: >>>> On Wed, Mar 23, 2011 at 4:06 PM, Arne Jansen<sensi...@gmx.net> wrote: >>>>> The main idea is to load the tree (or parts of it) top-down, order the >>>>> needed blocks and distribute it over all disks. >>>>> To keep you interested, some results first. >>>>> >>>>> a) by tree enumeration with reada=2 >>>>> reading extent tree: 242s >>>>> reading csum tree: 140s >>>>> reading both trees: 324s >>>>> >>>>> b) prefetch prototype >>>>> reading extent tree: 23.5s >>>>> reading csum tree: 20.4s >>>>> reading both trees: 25.7s >>>> >>>> 10x speed-up looks indeed impressive. Just for me to be sure, did I >>>> get you right in that you attribute this effect specifically to >>>> enumerating tree leaves in key address vs. disk addresses when these >>>> two are not aligned? >>> >>> Yes. Leaves and the intermediate nodes tend to be quite scattered >>> around the disk with respect to their logical order. >>> Reading them in logical (ascending/descending) order require lots >>> of seeks. >> >> I'm also dealing with tree fragmentation problem, I try to store the leaves >> which have the same parent closely. > > That's good to hear. Do you have already anything I can repeat the test > with?
It is still under developing.;) Thanks Miao > -Arne > >> >> Regards >> Miao >> > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majord...@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
