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         default:
  41             PrintError(core->vm_info, core, "Unknown yield strategy (%d) using GREEDY\n",core->vm_info->perf_options.yield_strategy.strategy);
  42             v3_yield(core,-1);
  43             break;
  44     }
  45 }
  46
  47
  48
  49 uint64_t v3_cycle_diff_in_usec(struct guest_info *core, uint64_t first, uint64_t second)
  50 {
  51     uint64_t cycle_diff = second - first;
  52     uint64_t mhz = (core->time_state.host_cpu_freq) / 1000; // KHZ->MHZ
  53
  54     return cycle_diff / mhz ;  // cycles / (millioncycles/sec) = sec/million = usec
  55 }
  56
  57 static void set_yield_defaults(struct v3_vm_info *vm)
  58 {
  59     vm->perf_options.yield_strategy.strategy = V3_DEFAULT_YIELD_STRATEGY;
  60     vm->perf_options.yield_strategy.threshold_usec = V3_DEFAULT_YIELD_THRESHOLD_USEC;
  61     vm->perf_options.yield_strategy.time_usec = V3_DEFAULT_YIELD_TIME_USEC;
  62 }
  63
  64
  65 static void set_yield(struct v3_vm_info *vm, v3_cfg_tree_t *cfg)
  66
  67 {
  68     char *t;
  69
  70     set_yield_defaults(vm);
  71
  72     // now override
  73
  74     t = v3_cfg_val(cfg, "strategy");
  75
  76     if (t) {
  77         if (!strcasecmp(t,"greedy")) {
  78             vm->perf_options.yield_strategy.strategy = V3_YIELD_STRATEGY_GREEDY;
  79             V3_Print(vm, VCORE_NONE, "Setting yield strategy to GREEDY\n");
  80         } else if (!strcasecmp(t, "friendly")) {
  81             vm->perf_options.yield_strategy.strategy = V3_YIELD_STRATEGY_FRIENDLY;
  82             V3_Print(vm, VCORE_NONE, "Setting yield strategy to FRIENDLY\n");
  83         } else if (!strcasecmp(t, "adaptive")) {
  84             vm->perf_options.yield_strategy.strategy = V3_YIELD_STRATEGY_ADAPTIVE;
  85             V3_Print(vm, VCORE_NONE, "Setting yield strategy to ADAPTIVE\n");
  86         } else {
  87             V3_Print(vm, VCORE_NONE, "Unknown yield strategy '%s', using default\n",t);
  88         }
  89     } else {
  90         V3_Print(vm, VCORE_NONE, "Yield strategy not given, using default\n");
  91     }
  92
  93     t = v3_cfg_val(cfg, "threshold");
  94
  95     if (t) {
  96         vm->perf_options.yield_strategy.threshold_usec = atoi(t);
  97         V3_Print(vm, VCORE_NONE, "Setting yield threshold to %llu\n",vm->perf_options.yield_strategy.threshold_usec);
  98     } else {
  99         V3_Print(vm, VCORE_NONE, "Yield threshold not given, using default\n");
 100     }
 101
 102
 103     t = v3_cfg_val(cfg, "time");
 104
 105     if (t) {
 106         vm->perf_options.yield_strategy.time_usec = atoi(t);
 107         V3_Print(vm, VCORE_NONE, "Setting yield time to %llu\n",vm->perf_options.yield_strategy.time_usec);
 108     } else {
 109         V3_Print(vm, VCORE_NONE, "Yield time not given, using default\n");
 110     }
 111
 112
 113 }
 114
 115
 116
 117
 118 /*
 119 <vm>
 120   <perftune>
 121      <group name="yield">
 122         <strategy>greedy,friendly,adaptive</strategy>
 123         <threshold>us</threshold>
 124         <time>us</time>
 125      </group>
 126      <group name="something else">
 127         <group-specific>....</group-specific>
 128      </group>
 129      ...
 130   </perftune>
 131 </vm>
 132 */
 133 int      v3_setup_performance_tuning(struct v3_vm_info *vm, v3_cfg_tree_t *cfg)
 134 {
 135     v3_cfg_tree_t *t = v3_cfg_subtree(cfg,"perftune");
 136
 137     if (!t) {
 138         V3_Print(vm, VCORE_NONE,  "No performance tuning tree - using defaults\n");
 139         set_yield_defaults(vm);
 140         return 0;
 141     }
 142
 143     t = v3_cfg_subtree(t,"group");
 144
 145     while (t) {
 146         char *id = v3_cfg_val(t,"name");
 147         if (!id) {
 148             V3_Print(vm, VCORE_NONE,  "Skipping performance parameter group without name\n");
 149         } else {
 150             if (!strcasecmp(id,"yield")) {
 151                 set_yield(vm,t);
 152             } else {
 153                 V3_Print(vm, VCORE_NONE,  "Skipping unknown performance parameter group\n");
 154             }
 155         }
 156         t = v3_cfg_next_branch(t);
 157     }
 158
 159     return 0;
 160 }
 161