On Tue 18-10-16 17:24:46, Dave Chinner wrote: > On Mon, Oct 17, 2016 at 10:22:56AM +0200, Michal Hocko wrote: > > On Mon 17-10-16 07:49:59, Dave Chinner wrote: > > > On Thu, Oct 13, 2016 at 01:04:56PM +0200, Michal Hocko wrote: > > > > On Thu 13-10-16 09:39:47, Michal Hocko wrote: > > > > > On Thu 13-10-16 11:29:24, Dave Chinner wrote: > > > > > > On Fri, Oct 07, 2016 at 03:18:14PM +0200, Michal Hocko wrote: > > > > > [...] > > > > > > > Unpatched kernel: > > > > > > > # Version 3.3, 16 thread(s) starting at Fri Oct 7 09:55:05 > > > > > > > 2016 > > > > > > > # Sync method: NO SYNC: Test does not issue sync() or > > > > > > > fsync() calls. > > > > > > > # Directories: Time based hash between directories across > > > > > > > 10000 subdirectories with 180 seconds per subdirectory. > > > > > > > # File names: 40 bytes long, (16 initial bytes of time > > > > > > > stamp with 24 random bytes at end of name) > > > > > > > # Files info: size 0 bytes, written with an IO size of > > > > > > > 16384 bytes per write > > > > > > > # App overhead is time in microseconds spent in the test > > > > > > > not doing file writing related system calls. > > > > > > > # > > > > > > > FSUse% Count Size Files/sec App Overhead > > > > > > > 1 1600000 0 4300.1 20745838 > > > > > > > 3 3200000 0 4239.9 23849857 > > > > > > > 5 4800000 0 4243.4 25939543 > > > > > > > 6 6400000 0 4248.4 19514050 > > > > > > > 8 8000000 0 4262.1 20796169 > > > > > > > 9 9600000 0 4257.6 21288675 > > > > > > > 11 11200000 0 4259.7 19375120 > > > > > > > 13 12800000 0 4220.7 22734141 > > > > > > > 14 14400000 0 4238.5 31936458 > > > > > > > 16 16000000 0 4231.5 23409901 > > > > > > > 18 17600000 0 4045.3 23577700 > > > > > > > 19 19200000 0 2783.4 58299526 > > > > > > > 21 20800000 0 2678.2 40616302 > > > > > > > 23 22400000 0 2693.5 83973996 > > > > > > > Ctrl+C because it just took too long. > > > > > > > > > > > > Try running it on a larger filesystem, or configure the fs with more > > > > > > AGs and a larger log (i.e. mkfs.xfs -f -dagcount=24 -l size=512m > > > > > > <dev>). That will speed up modifications and increase concurrency. > > > > > > This test should be able to run 5-10x faster than this (it > > > > > > sustains 55,000 files/s @ 300MB/s write on my test fs on a cheap > > > > > > SSD). > > > > > > > > > > Will add more memory to the machine. Will report back on that. > > > > > > > > increasing the memory to 1G didn't help. So I've tried to add > > > > -dagcount=24 -l size=512m and that didn't help much either. I am at 5k > > > > files/s so nowhere close to your 55k. I thought this is more about CPUs > > > > count than about the amount of memory. So I've tried a larger machine > > > > with 24 CPUs (no dagcount etc...), this one doesn't have a fast storage > > > > so I've backed the fs image by ramdisk but even then I am getting very > > > > similar results. No idea what is wrong with my kvm setup. > > > > > > What's the backing storage? I use an image file in an XFS > > > filesystem, configured with virtio,cache=none so it's concurrency > > > model matches that of a real disk... > > > > I am using qcow qemu image exported to qemu by > > -drive file=storage.img,if=ide,index=1,cache=none > > parameter. > > storage.img is on what type of filesystem?
ext3 on the host system > Only XFs will give you > proper IO concurrency with direct IO, and you really need to use a > raw image file rather than qcow2. If you're not using the special > capabilities of qcow2 (e.g. snapshots), there's no reason to use > it... OK, I will try with the raw image as soon as I have some more time (hopefully this week). Thanks -- Michal Hocko SUSE Labs
