From: Darius Rad <darius@bluespec.com>
Date: Tue, 22 May 2018 20:37:47 +0000 (-0400)
Subject: Set TCP_NODELAY for local connections to jtag_vpi.
X-Git-Tag: v0.11.0-rc1~944
X-Git-Url: https://review.openocd.org/gitweb?p=openocd.git;a=commitdiff_plain;h=eb8dfd5ca8af6f2d784f6b1d30c96b40c52ae0ce

Set TCP_NODELAY for local connections to jtag_vpi.

This increases performance drematically for local connections, which is the
most likely arrangement for a VPI connection.

Change-Id: Id15b29ae663f5d8100b2175357649bd03d05b7c8
Signed-off-by: Darius Rad <darius@bluespec.com>
Reviewed-on: http://openocd.zylin.com/4549
Tested-by: jenkins
Reviewed-by: Tomas Vanek <vanekt@fbl.cz>
---

diff --git a/src/jtag/drivers/jtag_vpi.c b/src/jtag/drivers/jtag_vpi.c
index 1a42b3a05f..35c70312d6 100644
--- a/src/jtag/drivers/jtag_vpi.c
+++ b/src/jtag/drivers/jtag_vpi.c
@@ -29,6 +29,10 @@
 #include <arpa/inet.h>
 #endif
 
+#ifndef _WIN32
+#include <netinet/tcp.h>
+#endif
+
 #define NO_TAP_SHIFT	0
 #define TAP_SHIFT	1
 
@@ -368,6 +372,8 @@ static int jtag_vpi_execute_queue(void)
 
 static int jtag_vpi_init(void)
 {
+	int flag = 1;
+
 	sockfd = socket(AF_INET, SOCK_STREAM, 0);
 	if (sockfd < 0) {
 		LOG_ERROR("Could not create socket");
@@ -395,6 +401,13 @@ static int jtag_vpi_init(void)
 		return ERROR_COMMAND_CLOSE_CONNECTION;
 	}
 
+	if (serv_addr.sin_addr.s_addr == htonl(INADDR_LOOPBACK)) {
+		/* This increases performance drematically for local
+		 * connections, which is the most likely arrangement
+		 * for a VPI connection. */
+		setsockopt(sockfd, IPPROTO_TCP, TCP_NODELAY, (char *)&flag, sizeof(int));
+	}
+
 	LOG_INFO("Connection to %s : %u succeed", server_address, server_port);
 
 	return ERROR_OK;