[openib-general] Re: [PATCH (updated)] ipoib: dont lock tx on completion

[Sean Hefty]

Michael S. Tsirkin wrote:

>>I don't see a specific race -- I'm just not totally comfortable yet,
>>even with that fixed.  The issue is not necessarily reads being
>>delayed, since both an out-of-order CPU and a compiler may move reads
>>much _earlier_ than they appear in the code (for example a read may be
>>speculatively executed because of branch prediction for a test in an
>>if statement).
>>
>> - R.
>>
> Can they be moved to before the wmb? I think not.

Given that there's some concern here regarding races, what sort of 
performance improvement do we see with this change?

- Sean