inform user when not running as root

[landroni]

I tried to run flashbench 62 (for Ubuntu repos) as user, only for it to fail with a cryptic error message:

geek@liv-inspiron:~$ flashbench -a /dev/sdb 
sched_setscheduler: Operation not permitted
/dev/sdb: Operation not permitted

Then I attempted as root, and it worked OK.

It would be nice if flashbench inform user that it only works as root.

[tomato42]

you don't have to be root, you need to have permission to write to block devices

[landroni]

Every time I try to run as simple user (i.e. non-root), I get the error above. I have no trouble writing to block devices using e.g. dd.

[bradfa]

In order to change the scheduler used, as flashbench does, you need to have CAP_SYS_NICE capability, so basically, you have to be root. Informing the user that the sched_setscheduler() call fails due to not being root or not having the proper capabilities is a reasonable feature.