--- /dev/null
+/*
+ * This file is part of the Palacios Virtual Machine Monitor developed
+ * by the V3VEE Project with funding from the United States National
+ * Science Foundation and the Department of Energy.
+ *
+ * The V3VEE Project is a joint project between Northwestern University
+ * and the University of New Mexico. You can find out more at
+ * http://www.v3vee.org
+ *
+ * Copyright (c) 2012, Peter Dinda <pdinda@northwestern.edu>
+ * Copyright (c) 2008, The V3VEE Project <http://www.v3vee.org>
+ * All rights reserved.
+ *
+ * Author: Peter Dinda <pdinda@northwestern.edu>
+ *
+ * This is free software. You are permitted to use,
+ * redistribute, and modify it as specified in the file "V3VEE_LICENSE".
+ */
+
+#ifndef __VM_PERFTUNE_H__
+#define __VM_PERFTUNE_H__
+
+#ifdef __V3VEE__
+
+#include <palacios/vmm_types.h>
+
+
+struct v3_yield_strategy {
+ enum {
+ V3_YIELD_STRATEGY_GREEDY=0, // always untimed yields
+ V3_YIELD_STRATEGY_FRIENDLY, // always timed yields with the following
+ V3_YIELD_STRATEGY_ADAPTIVE, // switch from untimed to timed after the threshold
+ } strategy;
+
+ uint64_t threshold_usec; // the point at which we transiton from untimed to timed yield
+ uint64_t time_usec; // the amount of time for a timed yield call
+
+#define V3_DEFAULT_YIELD_STRATEGY V3_YIELD_STRATEGY_GREEDY
+#define V3_DEFAULT_YIELD_THRESHOLD_USEC 100
+#define V3_DEFAULT_YIELD_TIME_USEC 1000
+};
+
+
+
+//
+// The idea is that the performance tuning knobs in the system are in the following
+// structure, which is configured when the VM is created, right after extensions,
+// using the <perftune/> subtree
+//
+struct v3_perf_options {
+ struct v3_yield_strategy yield_strategy;
+};
+
+
+int v3_setup_performance_tuning(struct v3_vm_info *vm, v3_cfg_tree_t *cfg);
+
+void v3_strategy_driven_yield(struct guest_info *core, uint64_t time_since_last_did_work_usec);
+
+uint64_t v3_cycle_diff_in_usec(struct guest_info *core, uint64_t earlier_cycles, uint64_t later_cycles);
+
+
+#endif
+
+#endif
--- /dev/null
+/*
+ * This file is part of the Palacios Virtual Machine Monitor developed
+ * by the V3VEE Project with funding from the United States National
+ * Science Foundation and the Department of Energy.
+ *
+ * The V3VEE Project is a joint project between Northwestern University
+ * and the University of New Mexico. You can find out more at
+ * http://www.v3vee.org
+ *
+ * Copyright (c) 2012, Peter Dinda <pdinda@northwestern.edu>
+ * Copyright (c) 2008, The V3VEE Project <http://www.v3vee.org>
+ * All rights reserved.
+ *
+ * Author: Peter Dinda <pdinda@northwestern.edu>
+ *
+ * This is free software. You are permitted to use,
+ * redistribute, and modify it as specified in the file "V3VEE_LICENSE".
+ */
+
+#include <palacios/vmm.h>
+#include <palacios/vm_guest.h>
+
+
+void v3_strategy_driven_yield(struct guest_info *core, uint64_t time_since_last_did_work_usec)
+{
+ // yield according to strategy
+ switch (core->vm_info->perf_options.yield_strategy.strategy) {
+ case V3_YIELD_STRATEGY_GREEDY:
+ v3_yield(core,-1);
+ break;
+ case V3_YIELD_STRATEGY_FRIENDLY:
+ v3_yield(core,core->vm_info->perf_options.yield_strategy.time_usec);
+ break;
+ case V3_YIELD_STRATEGY_ADAPTIVE:
+ if (time_since_last_did_work_usec > core->vm_info->perf_options.yield_strategy.threshold_usec) {
+ v3_yield(core,core->vm_info->perf_options.yield_strategy.time_usec);
+ } else {
+ v3_yield(core,-1);
+ }
+ default:
+ PrintError("Unknown yield strategy (%d) using GREEDY\n",core->vm_info->perf_options.yield_strategy.strategy);
+ v3_yield(core,-1);
+ break;
+ }
+}
+
+
+
+uint64_t v3_cycle_diff_in_usec(struct guest_info *core, uint64_t first, uint64_t second)
+{
+ uint64_t cycle_diff = second - first;
+ uint64_t mhz = (core->time_state.host_cpu_freq) / 1000; // KHZ->MHZ
+
+ return cycle_diff / mhz ; // cycles / (millioncycles/sec) = sec/million = usec
+}
+
+static void set_yield_defaults(struct v3_vm_info *vm)
+{
+ vm->perf_options.yield_strategy.strategy = V3_DEFAULT_YIELD_STRATEGY;
+ vm->perf_options.yield_strategy.threshold_usec = V3_DEFAULT_YIELD_THRESHOLD_USEC;
+ vm->perf_options.yield_strategy.time_usec = V3_DEFAULT_YIELD_TIME_USEC;
+}
+
+
+static void set_yield(struct v3_vm_info *vm, v3_cfg_tree_t *cfg)
+
+{
+ char *t;
+
+ set_yield_defaults(vm);
+
+ // now override
+
+ t = v3_cfg_val(cfg, "yield_strategy");
+
+ if (t) {
+ if (!strcasecmp(t,"greedy")) {
+ vm->perf_options.yield_strategy.strategy = V3_YIELD_STRATEGY_GREEDY;
+ V3_Print("Setting yield strategy to GREEDY\n");
+ } else if (!strcasecmp(t, "friendly")) {
+ vm->perf_options.yield_strategy.strategy = V3_YIELD_STRATEGY_FRIENDLY;
+ V3_Print("Setting yield strategy to FRIENDLY\n");
+ } else if (!strcasecmp(t, "adaptive")) {
+ vm->perf_options.yield_strategy.strategy = V3_YIELD_STRATEGY_ADAPTIVE;
+ V3_Print("Setting yield strategy to ADAPTIVE\n");
+ } else {
+ V3_Print("Unknown yield strategy '%s', using default\n",t);
+ }
+ } else {
+ V3_Print("Yield strategy not given, using default\n");
+ }
+
+ t = v3_cfg_val(cfg, "threshold");
+
+ if (t) {
+ vm->perf_options.yield_strategy.threshold_usec = atoi(t);
+ V3_Print("Setting yield threshold to %llu\n",vm->perf_options.yield_strategy.threshold_usec);
+ } else {
+ V3_Print("Yield threshold not given, using default\n");
+ }
+
+
+ t = v3_cfg_val(cfg, "time");
+
+ if (t) {
+ vm->perf_options.yield_strategy.time_usec = atoi(t);
+ V3_Print("Setting yield time to %llu\n",vm->perf_options.yield_strategy.time_usec);
+ } else {
+ V3_Print("Yield time not given, using default\n");
+ }
+
+
+}
+
+
+
+
+/*
+<vm>
+ <perftune>
+ <group name="yield_strategy">
+ <strategy>greedy,friendly,adaptive</strategy>
+ <threshold>us</threshold>
+ <time>us</time>
+ </group>
+ <group name="something else">
+ <group-specific>....</group-specific>
+ </group>
+ ...
+ </perftune>
+</vm>
+*/
+int v3_setup_performance_tuning(struct v3_vm_info *vm, v3_cfg_tree_t *cfg)
+{
+ v3_cfg_tree_t *t = v3_cfg_subtree(cfg,"perftune");
+
+ if (!t) {
+ V3_Print("No performance tuning tree - using defaults\n");
+ set_yield_defaults(vm);
+ return 0;
+ }
+
+ t = v3_cfg_subtree(t,"group");
+
+ while (t) {
+ char *id = v3_cfg_val(t,"name");
+ if (!id) {
+ V3_Print("Skipping performance parameter group without name\n");
+ } else {
+ if (!strcasecmp(id,"yield_strategy")) {
+ set_yield(vm,t);
+ } else {
+ V3_Print("Skipping unknown performance parameter group\n");
+ }
+ }
+ t = v3_cfg_next_branch(t);
+ }
+
+ return 0;
+}
+
