Re: Performance testing with bcache

[Sitsofe Wheeler <sitsofe@yahoo.com>]

On Fri, Mar 14, 2014 at 04:16:27PM -0500, Andrew Martin wrote:
> 
> Do you have an example fio job file that has worked well for testing
> bcache?

Try these as a starting point:
benchmark-seq.fio:
; Script to gather general sequential write performance statistics
; Basic usage:
; BS="4k" DEV="sdf" RT=90 SEED=21 TYPE="ssd" fio benchmark-seq.fio

[global]
filename=/dev/${DEV}
runtime=${RT}
bs=${BS}
iodepth=4
ioengine=libaio
direct=1
stonewall
size=${SIZE}
randseed=${SEED}
[write]
rw=write

benchmark-rand.fio:
; Script to gather general random write performance statistics
; Basic usage:
; BS="4k" DEV="sdf" RT=90 SEED=21 TYPE="ssd" fio benchmark-rand.fio

[global]
filename=/dev/${DEV}
runtime=${RT}
bs=${BS}
iodepth=4
ioengine=libaio
direct=1
stonewall
size=${SIZE}
randseed=${SEED}
[randwrite]
rw=randwrite

After making the above files do
export RT=30; export SEED=21; export SIZE="10G"; export DEV="bcache0"
for b in "4" "16" "64"; do export BS="${b}k"; for job in "benchmark-seq" "benchmark-rand"; do fio $job.fio; done; done

The first time round get the stats where the cache is not being used.
Next time round set the appropriate cache options (easier said than done
:-), run a single benchmark-seq.fio job (I'd recommend 64k blocksize) to
warm the cache then rerun the above.

Let us know what you did and how it went!

-- 
Sitsofe | http://sucs.org/~sits/