From 3030589aaafdba0a3b14183e0d03488580d21bf5 Mon Sep 17 00:00:00 2001
From: Jeff Forcier <jeff@bitprophet.org>
Date: Tue, 17 Jan 2012 12:10:57 -0800
Subject: [PATCH] Add IO sleep to agent forward communications.

Without this, use of agent forwarding causes
high CPU usage on some clients.
---
 ssh/__init__.py | 5 ++++-
 ssh/agent.py    | 2 ++
 ssh/common.py   | 3 +++
 3 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/ssh/__init__.py b/ssh/__init__.py
index 86dde0f..f00da10 100644
--- a/ssh/__init__.py
+++ b/ssh/__init__.py
@@ -98,6 +98,8 @@ from common import AUTH_SUCCESSFUL, AUTH_PARTIALLY_SUCCESSFUL, AUTH_FAILED, \
 from sftp import SFTP_OK, SFTP_EOF, SFTP_NO_SUCH_FILE, SFTP_PERMISSION_DENIED, SFTP_FAILURE, \
      SFTP_BAD_MESSAGE, SFTP_NO_CONNECTION, SFTP_CONNECTION_LOST, SFTP_OP_UNSUPPORTED
 
+from common import io_sleep
+
 __all__ = [ 'Transport',
             'SSHClient',
             'MissingHostKeyPolicy',
@@ -131,4 +133,5 @@ __all__ = [ 'Transport',
             'AgentKey',
             'HostKeys',
             'SSHConfig',
-            'util' ]
+            'util',
+            'io_sleep' ]
diff --git a/ssh/agent.py b/ssh/agent.py
index d8c52f1..e613531 100644
--- a/ssh/agent.py
+++ b/ssh/agent.py
@@ -34,6 +34,7 @@ from ssh.ssh_exception import SSHException
 from ssh.message import Message
 from ssh.pkey import PKey
 from ssh.channel import Channel
+from ssh.common import io_sleep
 
 SSH2_AGENTC_REQUEST_IDENTITIES, SSH2_AGENT_IDENTITIES_ANSWER, \
     SSH2_AGENTC_SIGN_REQUEST, SSH2_AGENT_SIGN_RESPONSE = range(11, 15)
@@ -134,6 +135,7 @@ class AgentProxyThread(threading.Thread):
                         self._agent._conn.send(data)
                     else:
                         break
+            time.sleep(io_sleep)
 
 class AgentLocalProxy(AgentProxyThread):
     """
diff --git a/ssh/common.py b/ssh/common.py
index 8f6a77c..4858200 100644
--- a/ssh/common.py
+++ b/ssh/common.py
@@ -124,3 +124,6 @@ INFO = logging.INFO
 WARNING = logging.WARNING
 ERROR = logging.ERROR
 CRITICAL = logging.CRITICAL
+
+# Common IO/select/etc sleep period, in seconds
+io_sleep = 0.01