svn commit: r294788 - head/sys/dev/hyperv/netvsc

[Gleb Smirnoff]

  Sepherosa,

On Tue, Jan 26, 2016 at 09:42:13AM +0000, Sepherosa Ziehau wrote:
S> Author: sephe
S> Date: Tue Jan 26 09:42:13 2016
S> New Revision: 294788
S> URL: https://svnweb.freebsd.org/changeset/base/294788
S> 
S> Log:
S>   hyperv/hn: Improve sending performance
S>   
S>   - Avoid main lock contention by trylock for if_start, if that fails,
S>     schedule TX taskqueue for if_start
S>   - Don't do direct sending if the packet to be sent is large, e.g.
S>     TSO packet.
S>   
S>   This change gives me stable 9.1Gbps TCP sending performance w/ TSO
S>   over a 10Gbe directly connected network (the performance fluctuated
S>   between 4Gbps and 9Gbps before this commit). It also improves non-
S>   TSO TCP sending performance a lot.
S>   
S>   Reviewed by:		adrian, royger
S>   Approved by:		adrian (mentor)
S>   Sponsored by:		Microsoft OSTC
S>   Differential Revision:	https://reviews.freebsd.org/D5074

Why do you actually use if_start, not if_transmit?

-- 
Totus tuus, Glebius.