PORTING: Add some minor clarifications.

diff --git a/PORTING b/PORTING
index 34c71f45c02cfd1075a2309e10b7245c97faf2fb..3dd0bfc5048dc199da27b1939b05c7bcbe747096 100644 (file)
--- a/PORTING
+++ b/PORTING
@@ -53,7 +53,7 @@ these components should not need to be modified as part of a port:
 
     - "ofproto" is the Open vSwitch library, in ofproto/, that
       implements an OpenFlow switch.  It talks to OpenFlow controllers
 
     - "ofproto" is the Open vSwitch library, in ofproto/, that
       implements an OpenFlow switch.  It talks to OpenFlow controllers

-      over the network and to switch hardware or software to an
+      over the network and to switch hardware or software through an

       "ofproto provider", explained further below.
 
     - "netdev" is the Open vSwitch library, in lib/netdev.c, that
       "ofproto provider", explained further below.
 
     - "netdev" is the Open vSwitch library, in lib/netdev.c, that


@@ -146,7 +146,11 @@ depends on a few different factors:
       other features.  An ofproto provider has to provide its own
       implementations, if the hardware can support them at all.
 
       other features.  An ofproto provider has to provide its own
       implementations, if the hardware can support them at all.
 

-    * A dpif provider is usually easier to implement.
+    * A dpif provider is usually easier to implement, but most
+      appropriate for software switching.  It "explodes" wildcard
+      rules into exact-match entries.  This allows fast hash lookups
+      in software, but makes inefficient use of TCAMs in hardware
+      that support wildcarding.

 
 The following sections describe how to implement each kind of port.
 
 
 The following sections describe how to implement each kind of port.
 


@@ -156,7 +160,7 @@ ofproto Providers
 
 An "ofproto provider" is what ofproto uses to directly monitor and
 control an OpenFlow-capable switch.  struct ofproto_class, in
 
 An "ofproto provider" is what ofproto uses to directly monitor and
 control an OpenFlow-capable switch.  struct ofproto_class, in

-ofproto/private.h, defines the interfaces to implement a ofproto
+ofproto/private.h, defines the interfaces to implement an ofproto

 provider for new hardware or software.  That structure contains many
 function pointers, each of which has a comment that is meant to
 describe its behavior in detail.  If the requirements are unclear,
 provider for new hardware or software.  That structure contains many
 function pointers, each of which has a comment that is meant to
 describe its behavior in detail.  If the requirements are unclear,


@@ -243,7 +247,7 @@ name makes the intended use obvious.
 
 ovs-vswitchd is the most sophisticated of ofproto's clients, but
 ofproto can have other clients as well.  test-openflowd, in the
 
 ovs-vswitchd is the most sophisticated of ofproto's clients, but
 ofproto can have other clients as well.  test-openflowd, in the

-tests directory, is much simpler than ovs-vswitchd.  It may be
+"tests" directory, is much simpler than ovs-vswitchd.  It may be

 easier to initially bring up test-openflowd as part of a port.
 
 lib/entropy.c assumes that it can obtain high-quality random number
 easier to initially bring up test-openflowd as part of a port.
 
 lib/entropy.c assumes that it can obtain high-quality random number