On 2021/08/06 10:43, Bart Van Assche wrote:
On 8/5/21 6:50 PM, yukuai (C) wrote:
After applying this configuration, the number of null_blk in my
machine is about 650k(330k before). Is this still too low?
That seems low to me. If I run the attached script on a six year old
desktop with an eight core i7-4790 CPU it reports a little more than 5
million IOPS. Has kernel debugging perhaps been enabled in the kernel on
the test setup? Or is the system perhaps slowed down by security
mitigations?
Hi, Bart
Sorry for the delay. I was too busy with other things recently.
After disable all the kernel debuging config I can think of, the
numbers can increase to millions.
setup cmd:
modprobe null_blk nr_devices=0 &&
udevadm settle &&
cd /sys/kernel/config/nullb &&
mkdir nullb0 &&
cd nullb0 &&
echo 0 > completion_nsec &&
echo 512 > blocksize &&
echo 0 > home_node &&
echo 0 > irqmode &&
echo 1024 > size &&
echo 0 > memory_backed &&
echo 2 > queue_mode &&
echo 1 > power ||
exit $?
test cmd:
fio -filename=/dev/nullb0 -name=test -ioengine=io_uring -direct=1
-numjobs=32 -iodepth=32 -bs=4k -rw=write -group_reporting -runtime=30
--thread --gtod_reduce=1 --ioscheduler=none -time_based
test result:
| test round | with this patch | without this patch |
| ---------- | --------------- | ------------------ |
| 1 | 4310k | 4265k |
| 2 | 4295k | 4327k |
| 3 | 4217k | 4213k |
| 4 | 4355k | 4236k |
| 5 | 4315k | 4337k |
| average | 4294k | 4275k |
Thanks
Kuai
