There's documentation for exactly this stuff, linked off the main page of the wiki: http://atlas.evilpiepirate.org/git/linux-bcache.git/tree/Documentation/bcache.txt?h=bcache-dev#n126 On Mon, Apr 29, 2013 at 8:43 AM, Leslie Basmid <leslie.basmid@xxxxxxxxx> wrote: > Hi all, > > I have chosen to install bcache using the bcache-for-upstream branch > (recompiled this morning for the latest patches). Even though > everything is running smoothly, I am surprised by the very poor > performance I'm obtaining from my setup. > > 1. Everything is setup on my laptop which has a 500GB HD (sda) and a > 16 GB SSD (sdb). > 2. I have setup an LVM above bcache, and /dev/sda4 is the only cache > partition. The whole thing was setup with: > > make-bcache -B /dev/sda4 -C /dev/sdb > > the LVM is "inside" /dev/sda4 > 3. I am using fio as a benchmark, have setup writeback > # cat /sys/block/bcache0/bcache/writeback_running > 1 > and I think I have followed every hints I could found about performance tuning. > Yet, when running the ssd fio test suite on a file on partition that > is not "cached", I am obtaining the following figures: > seq-read: iops=29156 > rand-read: iops=291 > seq-write: iops=22355 > rand-write: iops=260 > > Running it on a cached file system I'm obtaining: > seq-read: iops=22196 > rand-read: iops=330 > seq-write: iops=15864 > rand-write: iops=387 > > What am I missing ? > The benchmark parameters are: > bs=4k > ioengine=libaio > iodepth=64 > size=1g > direct=1 > > Thanks in advance for your answers, > Leslie. > -- > To unsubscribe from this list: send the line "unsubscribe linux-bcache" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-bcache" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
