What's the status of parallel netisr?

[Jian Qiu]

Thanks again for the info.

As you suggested, I did test on the most recent 7.0-stable-200807 kernel.

The SMP throughout on the new kernel was improved to around 90MB/s.

However, SMP kernel still had no advantage over UP, at least for this
kind of single threaded applications.

I further did the same test on Linux with both SMP and UP.

I did observe the same trend.

The throughput on UP (~210MB/ecs) was also much better than SMP (~170MB/sec).

However, I was surprised again that the local UDP throughput on Linux
was more than double of FreeBSD.

Since all these tests were performed on the same machine, it must be
because of the kernel that made such big differences.

I'm curious what is the major performance bottleneck in FreeBSD network stack??

Is there any plan in community to address these issues?

Many thanks.

Jian

On Wed, Sep 17, 2008 at 3:27 AM, Kris Kennaway <kris at freebsd.org> wrote:
> Jian Qiu wrote:
>>
>> Interesting.
>>
>> I did a test on local UDP throughput.
>>
>> I was surprised to find out the performance with a SMP kernel was
>> worse than UP. (~74MB/s v.s. 96 MB/s).
>>
>> I had though parallel netisr might be a solution.
>
> Make sure you are testing with either 8.0 or 7.1 (or late 7.0-STABLE), i.e.
> after the fixes to improve UDP performance on SMP systems.
>
> Kris
>
>