Mailinglist Archive: opensuse (1256 mails)

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[opensuse] Re: Is 40 dropped packets out of 300,000 high? This is wired cat5 LAN.
On Thu, 1 Jun 2017 14:19, Greg Freemyer wrote:
On Thu, Jun 1, 2017 at 6:25 AM, Carlos E. R. wrote:
On 2017-06-01 08:31, Per Jessen wrote:

Some more examples -

on machines with uptimes between 30 and 60 days, depending on their
load, I see drop rates of up to 1%. 0.99% on a xen guest, fairly busy.

On a mirror+squid, uptime 45days, I see 7% drop on one interface.

On four xen guests, not the most potent host machine, each has 10-11%
dropped rx packages ...

two webservers, uptime 1600 days and 92 days, 0 rx drops.

The only possible pattern here might be the xen guests which exhibit
somewhat higher rates than physical machines. My guess is that a
machine dropping packages is simply busy - too much incoming traffic or
too busy to process the interrupts.


The network "hardware" in the xen guest, is real or emulated?

Ignoring Per's issue.

My PC with the 6% dropped packets over some period of time is a
physical machine with a X99 MB and 64GB of RAM. No VM involved at
all. The 1Gbit NIC is built into the MB.

The CPU is 6 cores, 12 threads (via hyper-threading).

A real network card will have some internal memory and processing power,
and probably interrupts the machine only when the data chunk is ready.
Perhaps even moves the chunk to main ram via dma, thus no cpu load.

I wonder if my X99 MB truly has all that functionality?

Also, when I'm beating my NIC to death, I'm also hitting USB-3 hard.
I likely pulled down a couple TB of data via SMB and placed it on a
5TB USB-3 drive during the time I lost all those packets.

ie. rsync <SMB host> <USB-3 drive> (or equivalent drag & drop via dolphin)

It could well be that heavy USB-3 usage is interfering with my NIC?

Hmm, looking at Intels docu for the X99 chipset, it could well be.
The X99 PCH has a dedicated Gbit MAC integrated, and all the USBs
(3.0 and 2.0) are also handled by the PCH.
Also on the PCH are all the Sata, PCIe 2.0, M.2, and the Audio. All
that has to pass through the DMI 2.0 x4 (16 or 20Gbit) connect to the CPU.

The PCIe 3.0 and the RAM are connected directly to the CPU.

It could well be that the PCH has hiccups in the flow-control, and faces
the decission of mishandling the USB3 timing or dropping eth frames. (for overview)

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