From 5e9f9328696f8fb2a37b425112036cff5f319ee9 Mon Sep 17 00:00:00 2001
From: Stefan Lankes <slankes@eonerc.rwth-aachen.de>
Date: Mon, 22 Aug 2016 16:51:09 +0200
Subject: [PATCH] use busy waiting for receiving the IP address => reduce the
 latency

---
 hermit/kernel/main.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/hermit/kernel/main.c b/hermit/kernel/main.c
index 9a4e4ba5d..002394b97 100644
--- a/hermit/kernel/main.c
+++ b/hermit/kernel/main.c
@@ -228,7 +228,19 @@ success:
 		int mscnt = 0;
 		/* wait for ip address */
 		while(!default_netif.ip_addr.addr) {
+			uint64_t end_tsc, start_tsc = rdtsc();
+
+#if 1
+			do {
+				if (default_netif.ip_addr.addr)
+					return 0;
+				check_workqueues();
+				end_tsc = rdtsc();
+			} while(((end_tsc - start_tsc) / (get_cpu_frequency() * 1000)) < DHCP_FINE_TIMER_MSECS);
+#else
 			sys_msleep(DHCP_FINE_TIMER_MSECS);
+#endif
+
 			dhcp_fine_tmr();
 			mscnt += DHCP_FINE_TIMER_MSECS;
 			if (mscnt >= DHCP_COARSE_TIMER_SECS*1000) {
@@ -238,7 +250,6 @@ success:
 		}
 	}
 
-
 	return 0;
 }