CPU Transfer Bottleneck Question


Recommended Posts

Hi all,

 

I have an Asus C60M1-I and with DSM 6.2.3-25426 Update 3, 6 6TB WD Blues running on BM in RAID10 configuration. At baseline, idling, with the Realtek onboard NIC, CPU fluctuates between 10-40% use and I can get steady 58MBps read with 85%-ish CPU utilization.

 

With the onboard NIC disabled and an Intel i350-t4 installed with 2 port static LAG, CPU idles at 10%. Using single client pull, I can get >100MBps with occasional dips (disk I/O catching up?) with CPU use at around 65%. Performance with Intel i350-t4 is obviously better than the onboard NIC though I did run into a weird issue where I was only able to pull ~8MBps with this setup but this was fixed with a reboot. While pulling with 2 clients, I haven't been able to consistently break 1Gbps due to high CPU use.

 

On my genuine DS1518+ on RAID6 configuration also on static LAG, CPU utilization barely budged from low idle while pulling >100MBPs. On an ESXI VM (Dell T30 with i350-T4 vSwitch), I can also pull at >100MBps but with the CPU utilization barely budging.

 

There is no encryption on file transfers and I've tried both AFP & SMB with similar results for the C60M1-I in terms of utilization.

 

My two questions:

1) What's causing the high CPU utilization on file transfer with the C60M1-I that I'm not seeing on the DS1518+ and the VM?

2) I would like to be able to utilize the LAG on the C60M1-I but the bottleneck is the CPU, is there something I can do to lower the CPU utilization?

Edited by mic-cosmos
Link to post
Share on other sites
3 hours ago, mic-cosmos said:

On my genuine DS1518+ on RAID6 configuration also on static LAG, CPU utilization barely budged from low idle while pulling >100MBPs. On an ESXI VM (Dell T30 with i350-T4 vSwitch), I can also pull at >100MBps but with the CPU utilization barely budging.

ds1815+?

seems both are 4 core systems, having enough cpu cores for parallel threads seem still important, a 4 core cpu is suggested

i had a older core2quad for a while and no problems getting 1G nic speed, it looks like the amd 2 core cpu is holding the system from being faster

older amd cpu's are know to be slower at the same clock as intel and seeing that this cpu has just 1GHz ... and only 2 cores ...

 

you could fire up open media vault from a external media like usb, let the synology data volume mount ant try in network if it does more then dsm

maybe reasonably priced gemini lake (like in 920+) is a better alternative  - or waiting for some newer elkhart lake

https://www.dfi.com/product/index/1535

with its pcie 3.0 it can add a pcie ahci card capable of pcie 3.0 (5-6 ports like jmb585 or asm1166) and have a good performance (and if there is a 2.5Gbit realtek nic onboard you could have also some more network speed (intel 2.5G is not supported as intel does not deliver drivers outside kernel 5.x)

 

Link to post
Share on other sites

ASUS CPU is 1 Ghz.  DS1518+ is 2.4 Ghz.

 

Yes, buffering and and DMA and all that but IMHO this is one of those times that clock rate matters given the millions of packets and individual transactions that are trying to occur at line rate.  I think you are getting all you can out of that CPU.

Link to post
Share on other sites

Thanks both. I think it's obvious that CPU is the bottleneck here to get more than 1Gbps out of this system. What I'm surprised by is that I basically don't see any CPU utilization with my VM and DS1518+. With the CPU being the C60M1-I bottleneck, I would expect a small but noticeable increase in CPU use with the other two systems (given that they're 4 core with much faster clock) but I don't see that.

 

What are your experiences in your systems with file transfers in terms of CPU utilization? Small but noticeable or not at all with CPUs that are more beefy than on the C60M1-I?

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.