[Click] Packet loss even at low sending rate

[Bingyang LIU]

Hi~

I used CPUQueue and found that it didn't drop packets any more. So the only
problem is that PollDevice drops packets, actually I think it couldn't poll
all the ready packets from devices.

Does anyone has similar problem with PollDevice, and is there any solution
or best practices?

best
Bingyang

On Sun, Dec 4, 2011 at 2:10 PM, Bingyang LIU <bjornliu at gmail.com> wrote:

> Hi Cliff,
>
> I couldn't use multi-threading when using FromDevice. When I used
> multi-threading and FromDevice together, the system crashed. So I had to
> use single thread when using FromDevice, and use 4 threads when using
> PollDevice.
>
> The router I tested has four gigabit interfaces, each of which connected
> with a host. All hosts sent packets to each other at the given rate.
> When the sending rate is 50kpps (200kpps in total), FromDevice gave the
> output ratio of 99.74%, while PollDevice gave 99.94%.
> When the sending rate is 200kpps (800kpps in total), FromDevice only gave
> the output ratio of 62.63%, while PollDevice gave 99.29%.
>
> That's why I think PollDevice works much better than FromDevice. Actually,
> both of them cause some packet loss at low input rate.
>
> And I think click 1.8 is also a mainline source code. But you are right, I
> should try 2.0. However, I'm not sure whether the same thing will happen to
> 2.0.
>
> best
> Bingyang
>
>
>
>
> On Sun, Dec 4, 2011 at 2:29 AM, Cliff Frey <cliff at meraki.com> wrote:
>
>> What performance numbers did you see when using FromDevice instead of
>> PollDevice?
>>
>> Have you tried mainline click?
>>
>>
>> On Sat, Dec 3, 2011 at 10:57 PM, Bingyang Liu <bjornliu at gmail.com> wrote:
>>
>>> Thanks Cliff. Ya, I have tried fromdevice, and it gave worse
>>> performance.
>>>
>>> I think Queue should be a very mature element, and there should not be a
>>> bug there. But the experiment results told me that something got wrong.
>>> Should I use a thread safe queue instead of queue, when I use multithreads?
>>>
>>> Thanks
>>> Bingyang
>>>
>>> Sent from my iPhone
>>>
>>> On Dec 4, 2011, at 12:31 AM, Cliff Frey <cliff at meraki.com> wrote:
>>>
>>> You could try FromDevice instead of PollDevice.  I'd expect that it
>>> would work fine.  If it is not high performance enough, it would be great
>>> if you should share your performance numbers just to have another datapoint.
>>>
>>> I doubt that Queue has a bug, you could try latest click sources though
>>> just in case.  As for finding/fixing any polldevice issues, I don't have
>>> anything to help you there...
>>>
>>> Cliff
>>>
>>> On Sat, Dec 3, 2011 at 8:49 PM, Bingyang LIU <bjornliu at gmail.com> wrote:
>>>
>>>> Hi Cliff,
>>>>
>>>> Thank you very much for your help. I followed your suggestion and got
>>>> some results.
>>>>
>>>> 1. It turned out that "PollDevice" failed to get all the packets from
>>>> NIC, even if the packet sending rate is only 200kpps with the packet size
>>>> of 64B.
>>>> 2. I used "grep . /click/.e/*/drops", all of them reported 0 drops.
>>>> 3. I put a counter between every two connected elements, to determine
>>>> which element dropped packet. Finally I found a queue dropped packets,
>>>> because the downstream counter reported less "count" than the upstream one.
>>>> However, it was straight that this queue still reported 0 drops. I think
>>>> there might be some bug with the element, or I mis-used the elements.
>>>>
>>>> So I have two questions. First, how can I make PollDevice work better,
>>>> which means that it won't drop packets at low rate. (Should I use Stride
>>>> Scheduler?) Second, is there any bug with Queue in Click 1.8.0, in terms of
>>>> dropping packets without reporting the drops?
>>>>
>>>> My experiment environment and configuration:
>>>> * Hardware: CPU Inter Xeon X3210 (quad core at 2.13Ghz), 4GB RAM. (a
>>>> server on deterlab)
>>>> * Software: Ubuntu8.04 + Click1.8, with PollDevice and
>>>> multi-thread enabled.
>>>> * Configuration: ./configure
>>>> --with-linux=/usr/src/linux-2.6.24.7 --enable-ipsec --enable-warp9
>>>> --enable-multithread=4
>>>> * Installation: sudo click-install --thread=4 site7_router1.click
>>>>
>>>>  thanks!
>>>> best
>>>> Bingyang
>>>>
>>>> On Sat, Dec 3, 2011 at 12:42 PM, Cliff Frey <cliff at meraki.com> wrote:
>>>>
>>>
>>
>
>
> --
> Bingyang Liu
> Network Architecture Lab, Network Center,Tsinghua Univ.
> Beijing, China
> Home Page: http://netarchlab.tsinghua.edu.cn/~liuby
>



-- 
Bingyang Liu
Network Architecture Lab, Network Center,Tsinghua Univ.
Beijing, China
Home Page: http://netarchlab.tsinghua.edu.cn/~liuby