vm/sampling_profiler.cpp

   1 #include "master.hpp"
   2
   3 namespace factor
   4 {
   5
   6 profiling_sample_count profiling_sample_count::record_counts() volatile
   7 {
   8         atomic::fence();
   9         profiling_sample_count returned(
  10                 sample_count,
  11                 gc_sample_count,
  12                 jit_sample_count,
  13                 foreign_sample_count,
  14                 foreign_thread_sample_count);
  15         atomic::fetch_subtract(&sample_count, returned.sample_count);
  16         atomic::fetch_subtract(&gc_sample_count, returned.gc_sample_count);
  17         atomic::fetch_subtract(&jit_sample_count, returned.jit_sample_count);
  18         atomic::fetch_subtract(&foreign_sample_count, returned.foreign_sample_count);
  19         atomic::fetch_subtract(&foreign_thread_sample_count, returned.foreign_thread_sample_count);
  20         return returned;
  21 }
  22
  23 void profiling_sample_count::clear() volatile
  24 {
  25         sample_count = 0;
  26         gc_sample_count = 0;
  27         jit_sample_count = 0;
  28         foreign_sample_count = 0;
  29         foreign_thread_sample_count = 0;
  30         atomic::fence();
  31 }
  32
  33 profiling_sample::profiling_sample(factor_vm *vm,
  34         bool prolog_p,
  35         profiling_sample_count const &counts,
  36         cell thread)
  37         :
  38         counts(counts),
  39         thread(thread)
  40 {
  41         vm->record_callstack_sample(&callstack_begin, &callstack_end, prolog_p);
  42 }
  43
  44 void factor_vm::record_sample(bool prolog_p)
  45 {
  46         profiling_sample_count counts = safepoint.sample_counts.record_counts();
  47         if (!counts.empty())
  48                 samples.push_back(profiling_sample(this, prolog_p,
  49                         counts, special_objects[OBJ_CURRENT_THREAD]));
  50 }
  51
  52 void factor_vm::record_callstack_sample(cell *begin, cell *end, bool prolog_p)
  53 {
  54         *begin = sample_callstacks.size();
  55         stack_frame *frame = ctx->bottom_frame();
  56         if (prolog_p)
  57         {
  58                 assert(frame >= ctx->callstack_top);
  59                 stack_frame *next_frame = frame_successor(frame);
  60                 while (next_frame >= ctx->callstack_top)
  61                 {
  62                         sample_callstacks.push_back(frame_code(frame)->owner);
  63                         frame = next_frame;
  64                         next_frame = frame_successor(next_frame);
  65                 }
  66         }
  67         else
  68         {
  69                 while (frame >= ctx->callstack_top)
  70                 {
  71                         sample_callstacks.push_back(frame_code(frame)->owner);
  72                         frame = frame_successor(frame);
  73                 }
  74         }
  75
  76         *end = sample_callstacks.size();
  77 }
  78
  79 void factor_vm::set_sampling_profiler(fixnum rate)
  80 {
  81         bool sampling_p = !!rate;
  82         if (sampling_p == !!atomic::load(&sampling_profiler_p))
  83                 return;
  84
  85         if (sampling_p)
  86                 start_sampling_profiler(rate);
  87         else
  88                 end_sampling_profiler();
  89 }
  90
  91 void factor_vm::clear_samples()
  92 {
  93         // Swapping into temporaries releases the vector's allocated storage,
  94         // whereas clear() would leave the allocation as-is
  95         std::vector<profiling_sample> sample_graveyard;
  96         std::vector<cell> sample_callstack_graveyard;
  97         samples.swap(sample_graveyard);
  98         sample_callstacks.swap(sample_callstack_graveyard);
  99 }
 100
 101 void factor_vm::start_sampling_profiler(fixnum rate)
 102 {
 103         samples_per_second = rate;
 104         safepoint.sample_counts.clear();
 105         clear_samples();
 106         samples.reserve(10*rate);
 107         sample_callstacks.reserve(100*rate);
 108         atomic::store(&sampling_profiler_p, true);
 109         start_sampling_profiler_timer();
 110 }
 111
 112 void factor_vm::end_sampling_profiler()
 113 {
 114         atomic::store(&sampling_profiler_p, false);
 115         end_sampling_profiler_timer();
 116         record_sample(false);
 117 }
 118
 119 void factor_vm::primitive_sampling_profiler()
 120 {
 121         set_sampling_profiler(to_fixnum(ctx->pop()));
 122 }
 123
 124 void factor_vm::primitive_get_samples()
 125 {
 126         if (atomic::load(&sampling_profiler_p) || samples.empty()) {
 127                 ctx->push(false_object);
 128         } else {
 129                 data_root<array> samples_array(allot_array(samples.size(), false_object),this);
 130                 std::vector<profiling_sample>::const_iterator from_iter = samples.begin();
 131                 cell to_i = 0;
 132
 133                 for (; from_iter != samples.end(); ++from_iter, ++to_i)
 134                 {
 135                         data_root<array> sample(allot_array(7, false_object),this);
 136
 137                         set_array_nth(sample.untagged(),0,tag_fixnum(from_iter->counts.sample_count));
 138                         set_array_nth(sample.untagged(),1,tag_fixnum(from_iter->counts.gc_sample_count));
 139                         set_array_nth(sample.untagged(),2,tag_fixnum(from_iter->counts.jit_sample_count));
 140                         set_array_nth(sample.untagged(),3,tag_fixnum(from_iter->counts.foreign_sample_count));
 141                         set_array_nth(sample.untagged(),4,tag_fixnum(from_iter->counts.foreign_thread_sample_count));
 142
 143                         set_array_nth(sample.untagged(),5,from_iter->thread);
 144
 145                         cell callstack_size = from_iter->callstack_end - from_iter->callstack_begin;
 146                         data_root<array> callstack(allot_array(callstack_size,false_object),this);
 147
 148                         std::vector<cell>::const_iterator
 149                                 callstacks_begin = sample_callstacks.begin(),
 150                                 c_from_iter = callstacks_begin + from_iter->callstack_begin,
 151                                 c_from_iter_end = callstacks_begin + from_iter->callstack_end;
 152                         cell c_to_i = 0;
 153
 154                         for (; c_from_iter != c_from_iter_end; ++c_from_iter, ++c_to_i)
 155                                 set_array_nth(callstack.untagged(),c_to_i,*c_from_iter);
 156
 157                         set_array_nth(sample.untagged(),6,callstack.value());
 158
 159                         set_array_nth(samples_array.untagged(),to_i,sample.value());
 160                 }
 161                 ctx->push(samples_array.value());
 162         }
 163 }
 164
 165 void factor_vm::primitive_clear_samples()
 166 {
 167         clear_samples();
 168 }
 169
 170 }