nvd0 lockup while compiling ports

[Warner Losh]

On Wed, Oct 4, 2017 at 6:03 AM, Gerhard Schmidt <estartu at ze.tum.de> wrote:

> Hi,
>
> I've got a new Workstation last week with the Main HD as M2 Card.
>
> FreeBSD recognizes the card as nvd0
> nvd0: <Samsung SSD 960 PRO 512GB> NVMe namespace
> nvd0: 488386MB (1000215216 512 byte sectors)
>
> When compiling some ports (in this example VirtualBox-ose) I
> experiencing lockups on the Harddisk when many files are deleted.
>
> here is the entries gstat reports
>
> dT: 1.064s  w: 1.000s
>  L(q)  ops/s    r/s   kBps   ms/r    w/s   kBps   ms/w   %busy Name
>  25281    769      0      0    0.0      0      0    0.0  100.0| nvd0
>  25279    769      0      0    0.0      0      0    0.0  100.0| nvd0p4
>  25279    769      0      0    0.0      0      0    0.0  100.0| ufs/USR
>
> here the right part of gstat -d -o
>
> dT: 1.003s  w: 1.000s
>     d/s   kBps   ms/d    o/s   ms/o   %busy Name
>     770  24641  31965      0    0.0  100.1| nvd0
>     770  24641  31965      0    0.0  100.1| nvd0p4
>     770  24641  31965      0    0.0  100.1| ufs/USR
>
> the numbers under L(q) go up to about 160000 and as long as theses
> operations are not finisched, no outer file operation is possible on
> this filesystem.
>
> The number of ops/s and d/s is constant aproximatly 770.
>
> Is there a way to speed up delete operations or limit the queue length?
>

Try disabling TRIM.

Warner