From: Peter Dinda <pdinda@northwestern.edu>
Date: Thu, 9 Aug 2012 18:48:49 +0000 (-0500)
Subject: Halt handling uses global performance parameters to decide yield strategy
X-Git-Url: http://v3vee.org/palacios/gitweb/gitweb.cgi?a=commitdiff_plain;h=5f9290a9547c1497c6070b35e32caa7fc388d189;p=palacios.releases.git

Halt handling uses global performance parameters to decide yield strategy
---

diff --git a/palacios/src/palacios/vmm_halt.c b/palacios/src/palacios/vmm_halt.c
index 604d06b..b6e1a96 100644
--- a/palacios/src/palacios/vmm_halt.c
+++ b/palacios/src/palacios/vmm_halt.c
@@ -21,6 +21,7 @@
 #include <palacios/vmm_halt.h>
 #include <palacios/vmm_intr.h>
 #include <palacios/vmm_lowlevel.h> 
+#include <palacios/vmm_perftune.h>
 
 #ifndef V3_CONFIG_DEBUG_HALT
 #undef PrintDebug
@@ -28,11 +29,6 @@
 #endif
 
 
-#define NO_PROGRESS_CYCLE_LIMIT  4000000ULL   // 4 million cycles, about 1ms on a 4 GHz machine
-
-#define YIELD_TIME_USEC    1000
-
-
 //
 // This should trigger a #GP if cpl != 0, otherwise, yield to host
 //
@@ -43,33 +39,22 @@ int v3_handle_halt(struct guest_info * info)
     if (info->cpl != 0) { 
 	v3_raise_exception(info, GPF_EXCEPTION);
     } else {
-	uint64_t total_cycles;
+	uint64_t start_cycles;
 	
-
 	PrintDebug("CPU Yield\n");
 
-	total_cycles = 0;
+	start_cycles  = v3_get_host_time(&info->time_state);
 
 	while (!v3_intr_pending(info) && (info->vm_info->run_state == VM_RUNNING)) {
             uint64_t t, cycles;
-	    /* Yield, allowing time to pass while yielded */
+
 	    t = v3_get_host_time(&info->time_state);
 
-	    // adaptively select the best yield option
-	    if (total_cycles > NO_PROGRESS_CYCLE_LIMIT) { 
-		// Slow yield - will take at least YIELD_TIME_USEC to come back
-		v3_yield(info,YIELD_TIME_USEC);
-	    } else {
-		// Fast yield - may come back immediately
-		v3_yield(info,-1);
-	    }
+	    /* Yield, allowing time to pass while yielded */
+	    v3_strategy_driven_yield(info, v3_cycle_diff_in_usec(info, start_cycles, t));
 
 	    cycles = v3_get_host_time(&info->time_state) - t;
 
-	    if ((total_cycles + cycles) > total_cycles) { 
-		total_cycles += cycles;
-	    }
-
 	    v3_advance_time(info, &cycles);
 
 	    v3_update_timers(info);