Re: Why fio triggers reading of device serial number

[Jens Axboe <axboe@xxxxxxxxx>]

On 05/18/2012 08:28 AM, Asias He wrote:
> Hi, List
> 
> I noticed that fio triggers reading of device serial number when fio
> starts (one read) and stops (lots of read). I was wondering if fio was
> reading the sysfs attribute directly in fio's code,
> e.g./sys/block/vda/serial, or it triggered something which make udevd to
> read it.
> 
> trace-cmd shows it seems udevd is reading:
> 
> udevd-6856  [006] xxx: function:    dev_attr_show
> udevd-6856  [006] xxx: function:        virtblk_serial_show
> 
> Any ideas? Thanks.

Probably mtime changing of the special file inode, causing some udev
rule to attempt to re-read the id/serial. Fio doesn't read the serial
number.

-- 
Jens Axboe

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