[openib-general] Re: ipoib_reap_ah question

[Roland Dreier]

    Shirley> Hello Roland, Is there any particular reason to use
    Shirley> ipoib_reap_ah thread?

    Shirley> In my tx_ring removal patch, I tested without
    Shirley> ipoib_reap_ah work queue by simply adding kref_get(),
    Shirley> kref_put() in ipoib_send(), and i didn't see any
    Shirley> difference including performance. If there is no other
    Shirley> risk, I will remove it to make it simple.

Using kref_get() and kref_put() adds an atomic operation to the data
path.  You may not be measuring the cost but an atomic operation is
just about the most expensive thing you can do.

I think you should keep your patches simple -- "one idea per patch."
So if you want to experiment with both tx_ring removal and the reap_ah
removal, keep in mind that they should be merged as separate patches.
So you should probably develop them that way.

 - R.