If you don’t have a pmem device, Linux can emulate one using RAM and the
‘memmap’ kernel parameter. See
http://pmem.io/2016/02/22/pm-emulation.html for more info.
Rebecca
Sent from my iPhone
On Nov 27, 2017, at 12:38 PM, Sitsofe Wheeler <sitsofe@xxxxxxxxx
<mailto:sitsofe@xxxxxxxxx>> wrote:
Unfortunately I don't have access to a pmem device but let's see how
far we get:
On 27 November 2017 at 12:39, Gavriliuk, Anton (HPS Ukraine)
<anton.gavriliuk@xxxxxxx <mailto:anton.gavriliuk@xxxxxxx>> wrote:
result=$(fio --name=random-writers --ioengine=mmap --iodepth=32
--rw=randwrite --bs=64k --size=1024m --numjobs=8 --group_reporting=1
--eta=never --time_based --runtime=60 --filename=/dev/dax0.0 | grep
WRITE)
Please make your problem scenarios as simple as possible:
1. Just run fio normally so we can see the output it produces on both
stdout and stderr normally.
2. Reduce the job back so it there are only the bare minimum options
that reproduce the problem.
3. Try to avoid changing lots of things.
Here you've switched ioengine introducing another place to look.
Instead how about this:
Was your /dev/dax0.0 device made using ndctl? Assuming yes:
fio --name=dax-mmap --ioengine=mmap --rw=write --bs=64k --eta=never
--time_based --runtime=60 --filename=/dev/dax0.0 --size=2g
(apparently a size has to be specified when you try to use a character
device - see https://nvdimm.wiki.kernel.org/ )
If you run just that by itself what do you see?
Next up:
fio --name=dax-dax --ioengine=dev-dax --rw=write --bs=64k --eta=never
--time_based --runtime=60 --filename=/dev/dax0.0 --size=2g
If you run just that by itself what do you see?
Finally:
Assuming a -o dax mounted filesystem on /pmem0/ :
fio --name=libpmemblk --ioengine=pmemblk --rw=write --bs=64k
--eta=never --time_based --runtime=60
--filename=/pmem0/fio-test,4096,1024 --thread=1
If you run just that by itself what do you see?
(Perhaps the documentation for these ioengines and pmem devices needs
to be improved?)
--
Sitsofe | http://sucs.org/~sits/ <http://sucs.org/%7Esits/>
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