Hello, Helmut.
On Mon, Feb 04, 2019 at 12:01:33 +0100, Helmut Jarausch wrote:
> I have a very fast Samsung NVME drive hosting my root file system.
> During backup 'atop' often shows 100% usage of my NVME drive while
> reading only a few MB/s and
> several thousands 'Read' ops (during 10 seconds).
> Is this normal or a measuring bug of 'atop'.
> Stand alone timing tests have shown that this drive can read some GB
> per second.
> What's happening?
I don't understand this well myself, but please make sure you've got
CONFIG_PCI_MSI ("message signalled interrupts") enabled in your kernel.
This was a tip from Adam Carter to me in 2017-04, when my new Samsung
NVMe drive wasn't performing to expectations, and it helped greatly.
> Many thanks for a hint,
> Helmut
--
Alan Mackenzie (Nuremberg, Germany).
