Re: skbuff truesize incorrect.

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On 05/23/2014 02:33 AM, Bjørn Mork wrote:
Jim Baxter <jim_baxter@xxxxxxxxxx> writes:

I'll create and test a patch for the cdc_ncm host driver unless someone
else wants to do that. I haven't really played with the gadget driver
before, so I'd prefer if someone knowing it (Jim maybe?) could take care
of it.  If not, then I can always make an attempt using dummy_hcd to
test it.
I can create a patch for the host driver, I will issue the gadget patch
first to resolve any issues, the fix would be similar.

Well, I couldn't help myself.  I just had to test it.  The attached
patch works for me, briefly tested with an Ericsson H5321gw NCM device.
I have no ideas about the performance impact as that modem is limited to
21 Mbps HSDPA.

If you are measuring performance with the likes of netperf, you should be able to get an idea of the performance effect from the change in service demand (CPU consumed per unit of work) even if the maximum throughput remains capped.

You can run a netperf TCP_STREAM test along the lines of:

netperf -H <otherguy> -c -C -t TCP_STREAM

and also

netperf -H <otherguy> -c -C -t TCP_RR

For extra added credit you can consider either multiple runs and post-processing, or adding a -i 30,3 to the command line to tell netperf to run at least three iterations, no more than thirty and it will try to achieve a 99% confidence that the reported means for throughput, local and remote CPU utilization are within +/- 2.5% of the actual mean. You can narrow or widen that with a -I 99,<width>. A width of 5% is what gives the +/- 2.5% (and/or demonstrates my lack of accurate statistics knowledge :) )

happy benchmarking,

rick jones

--
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html




[Index of Archives]     [Linux Media]     [Linux Input]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]     [Old Linux USB Devel Archive]

  Powered by Linux