Download Station / SMB crazy CPU usage and slowness

[Tibag]

Hi,

 

I started to have perf issues, or realise these, on my DSM 6.2.3-25426 U3 with Download Station and Samba file service. When downloading with DS I can see the CPU is hammered and it often looks like:

 

ie we can see DS sucking 100%, RAM fully allocated (mostly by rsyslog) but unused, some kswap process here and there. End result is DS is stuck at 5 Mb/s when my Internet allows 100 Mb/s (1 G provider).

 

I realised Samba shares are equally slow, if not worst. When I am copying a file to my Windows machine, all on a 1G switch, the speed will vary between 20Mb and 100kb/s. When this happens I can see smb process swallowing the CPU.

 

I can't tell if these two are related! I checked the Disk speed via DSM tool and it looked fine. I am using ESXI 6.5 VM for DSM. 

 

Any idea guys?