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