On 03/07/2016 02:02 PM, Andrey Kuzmin wrote:
On Mon, Mar 7, 2016 at 11:46 PM, Jeff Furlong <jeff.furlong@xxxxxxxx> wrote:
Thanks for the suggestions and patches. Using the latest fio version, the JESD219 workload is possible:
Nice.
# fio -version
fio-2.6-27-gd283
# fio --name=JESD219 --ioengine=libaio --direct=1 --rw=randrw --norandommap --randrepeat=0 --rwmixread=40 --rwmixwrite=60 --iodepth=256 --size=100% --numjobs=4 --bssplit=512/4:1024/1:1536/1:2048/1:2560/1:3072/1:3584/1:4k/67:8k/10:16k/7:32k/3:64k/3 --random_distribution=zoned:50/5:30/15:20/80 --overwrite=1 --filename=/dev/nvme0n1 --group_reporting --runtime=5m --time_based --output=JESD219
A quick statistical analysis of the results shows:
Found 20380582 IOs
Found 39.9903152913% reads
Found 60.0096847087% writes
Found 4.00492979052% 512
Found 1.00495658073% 1024
Found 1.00079575745% 1536
Found 1.00046701316% 2048
Found 0.998764412125% 2560
Found 0.998043137335% 3072
Found 0.999520033334% 3584
Found 67.0145778958% 4096
Found 9.98662844859% 8192
Found 6.99898560306% 16384
Found 2.99961993235% 32768
Found 2.99271139558% 65536
Found 49.9895734086% 0-5%
Found 30.0126463513% 5-20%%
Found 19.99778024% 20-100%
It hardly matters, but is still somewhat surprising to see that both
bs and zone split percentage are accurate only up to 5x10^-3.
It tends to be more accurate with more IOs - for this case, it's 20
million, I guess you could assume that it'd be better. Generally it does
get more accurate with more ios. But I'm mostly in the camp of "it
hardly matters", it's close enough that you'd be hard pressed to
complain about it.
Fio does most of its math in integers, so we lose a bit of precision
there, but it's a lot faster.
That said, just a one-off in the calculations here could mean that it's
an order of magnitude less accurate than it should. Maybe the above
could be 10^-4 or 10^-5. It's so close that I'm finding it hard to
locate the motivation to actually check and verify all that :-)
--
Jens Axboe
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