palacios/src/palacios/vmm_perftune.c

   1 /*
   2  * This file is part of the Palacios Virtual Machine Monitor developed
   3  * by the V3VEE Project with funding from the United States National
   4  * Science Foundation and the Department of Energy.
   5  *
   6  * The V3VEE Project is a joint project between Northwestern University
   7  * and the University of New Mexico.  You can find out more at
   8  * http://www.v3vee.org
   9  *
  10  * Copyright (c) 2012, Peter Dinda <pdinda@northwestern.edu>
  11  * Copyright (c) 2008, The V3VEE Project <http://www.v3vee.org>
  12  * All rights reserved.
  13  *
  14  * Author: Peter Dinda <pdinda@northwestern.edu>
  15  *
  16  * This is free software.  You are permitted to use,
  17  * redistribute, and modify it as specified in the file "V3VEE_LICENSE".
  18  */
  19
  20 #include <palacios/vmm.h>
  21 #include <palacios/vm_guest.h>
  22
  23
  24 void     v3_strategy_driven_yield(struct guest_info *core, uint64_t time_since_last_did_work_usec)
  25 {
  26     // yield according to strategy
  27     switch (core->vm_info->perf_options.yield_strategy.strategy) {
  28         case V3_YIELD_STRATEGY_GREEDY:
  29             v3_yield(core,-1);
  30             break;
  31         case V3_YIELD_STRATEGY_FRIENDLY:
  32             v3_yield(core,core->vm_info->perf_options.yield_strategy.time_usec);
  33             break;
  34         case V3_YIELD_STRATEGY_ADAPTIVE:
  35             if (time_since_last_did_work_usec > core->vm_info->perf_options.yield_strategy.threshold_usec) {
  36                 v3_yield(core,core->vm_info->perf_options.yield_strategy.time_usec);
  37             } else {
  38                 v3_yield(core,-1);
  39             }
  40             break;
  41         default:
  42             PrintError(core->vm_info, core, "Unknown yield strategy (%d) using GREEDY\n",core->vm_info->perf_options.yield_strategy.strategy);
  43             v3_yield(core,-1);
  44             break;
  45     }
  46 }
  47
  48
  49
  50 uint64_t v3_cycle_diff_in_usec(struct guest_info *core, uint64_t first, uint64_t second)
  51 {
  52     uint64_t cycle_diff = second - first;
  53     uint64_t mhz = (core->time_state.host_cpu_freq) / 1000; // KHZ->MHZ
  54
  55     return cycle_diff / mhz ;  // cycles / (millioncycles/sec) = sec/million = usec
  56 }
  57
  58 static void set_yield_defaults(struct v3_vm_info *vm)
  59 {
  60     vm->perf_options.yield_strategy.strategy = V3_DEFAULT_YIELD_STRATEGY;
  61     vm->perf_options.yield_strategy.threshold_usec = V3_DEFAULT_YIELD_THRESHOLD_USEC;
  62     vm->perf_options.yield_strategy.time_usec = V3_DEFAULT_YIELD_TIME_USEC;
  63 }
  64
  65
  66 static void set_yield(struct v3_vm_info *vm, v3_cfg_tree_t *cfg)
  67
  68 {
  69     char *t;
  70
  71     set_yield_defaults(vm);
  72
  73     // now override
  74
  75     t = v3_cfg_val(cfg, "strategy");
  76
  77     if (t) {
  78         if (!strcasecmp(t,"greedy")) {
  79             vm->perf_options.yield_strategy.strategy = V3_YIELD_STRATEGY_GREEDY;
  80             V3_Print(vm, VCORE_NONE, "Setting yield strategy to GREEDY\n");
  81         } else if (!strcasecmp(t, "friendly")) {
  82             vm->perf_options.yield_strategy.strategy = V3_YIELD_STRATEGY_FRIENDLY;
  83             V3_Print(vm, VCORE_NONE, "Setting yield strategy to FRIENDLY\n");
  84         } else if (!strcasecmp(t, "adaptive")) {
  85             vm->perf_options.yield_strategy.strategy = V3_YIELD_STRATEGY_ADAPTIVE;
  86             V3_Print(vm, VCORE_NONE, "Setting yield strategy to ADAPTIVE\n");
  87         } else {
  88             V3_Print(vm, VCORE_NONE, "Unknown yield strategy '%s', using default\n",t);
  89         }
  90     } else {
  91         V3_Print(vm, VCORE_NONE, "Yield strategy not given, using default\n");
  92     }
  93
  94     t = v3_cfg_val(cfg, "threshold");
  95
  96     if (t) {
  97         vm->perf_options.yield_strategy.threshold_usec = atoi(t);
  98         V3_Print(vm, VCORE_NONE, "Setting yield threshold to %llu\n",vm->perf_options.yield_strategy.threshold_usec);
  99     } else {
 100         V3_Print(vm, VCORE_NONE, "Yield threshold not given, using default\n");
 101     }
 102
 103
 104     t = v3_cfg_val(cfg, "time");
 105
 106     if (t) {
 107         vm->perf_options.yield_strategy.time_usec = atoi(t);
 108         V3_Print(vm, VCORE_NONE, "Setting yield time to %llu\n",vm->perf_options.yield_strategy.time_usec);
 109     } else {
 110         V3_Print(vm, VCORE_NONE, "Yield time not given, using default\n");
 111     }
 112
 113
 114 }
 115
 116
 117
 118
 119 /*
 120 <vm>
 121   <perftune>
 122      <group name="yield">
 123         <strategy>greedy,friendly,adaptive</strategy>
 124         <threshold>us</threshold>
 125         <time>us</time>
 126      </group>
 127      <group name="something else">
 128         <group-specific>....</group-specific>
 129      </group>
 130      ...
 131   </perftune>
 132 </vm>
 133 */
 134 int      v3_setup_performance_tuning(struct v3_vm_info *vm, v3_cfg_tree_t *cfg)
 135 {
 136     v3_cfg_tree_t *t = v3_cfg_subtree(cfg,"perftune");
 137
 138     if (!t) {
 139         V3_Print(vm, VCORE_NONE,  "No performance tuning tree - using defaults\n");
 140         set_yield_defaults(vm);
 141         return 0;
 142     }
 143
 144     t = v3_cfg_subtree(t,"group");
 145
 146     while (t) {
 147         char *id = v3_cfg_val(t,"name");
 148         if (!id) {
 149             V3_Print(vm, VCORE_NONE,  "Skipping performance parameter group without name\n");
 150         } else {
 151             if (!strcasecmp(id,"yield")) {
 152                 set_yield(vm,t);
 153             } else {
 154                 V3_Print(vm, VCORE_NONE,  "Skipping unknown performance parameter group\n");
 155             }
 156         }
 157         t = v3_cfg_next_branch(t);
 158     }
 159
 160     return 0;
 161 }
 162