[ovs-dev] [PATCH 1/2] PORTING: Add some minor clarifications.
Justin Pettit
jpettit at nicira.com
Fri Jul 1 21:18:49 UTC 2011
---
PORTING | 12 ++++++++----
1 files changed, 8 insertions(+), 4 deletions(-)
diff --git a/PORTING b/PORTING
index 34c71f4..3dd0bfc 100644
--- 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
- 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
@@ -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.
- * 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.
@@ -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
-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,
@@ -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
-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
--
1.7.1
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