29 |
29 |
30 // We measure the demand between the end of the previous sweep and |
30 // We measure the demand between the end of the previous sweep and |
31 // beginning of this sweep: |
31 // beginning of this sweep: |
32 // Count(end_last_sweep) - Count(start_this_sweep) |
32 // Count(end_last_sweep) - Count(start_this_sweep) |
33 // + splitBirths(between) - splitDeaths(between) |
33 // + splitBirths(between) - splitDeaths(between) |
34 // The above number divided by the time since the start [END???] of the |
34 // The above number divided by the time since the end of the |
35 // previous sweep gives us a time rate of demand for blocks |
35 // previous sweep gives us a time rate of demand for blocks |
36 // of this size. We compute a padded average of this rate as |
36 // of this size. We compute a padded average of this rate as |
37 // our current estimate for the time rate of demand for blocks |
37 // our current estimate for the time rate of demand for blocks |
38 // of this size. Similarly, we keep a padded average for the time |
38 // of this size. Similarly, we keep a padded average for the time |
39 // between sweeps. Our current estimate for demand for blocks of |
39 // between sweeps. Our current estimate for demand for blocks of |
40 // this size is then simply computed as the product of these two |
40 // this size is then simply computed as the product of these two |
41 // estimates. |
41 // estimates. |
42 AdaptivePaddedAverage _demand_rate_estimate; |
42 AdaptivePaddedAverage _demand_rate_estimate; |
43 |
43 |
44 ssize_t _desired; // Estimate computed as described above |
44 ssize_t _desired; // Demand stimate computed as described above |
45 ssize_t _coalDesired; // desired +/- small-percent for tuning coalescing |
45 ssize_t _coalDesired; // desired +/- small-percent for tuning coalescing |
46 |
46 |
47 ssize_t _surplus; // count - (desired +/- small-percent), |
47 ssize_t _surplus; // count - (desired +/- small-percent), |
48 // used to tune splitting in best fit |
48 // used to tune splitting in best fit |
49 ssize_t _bfrSurp; // surplus at start of current sweep |
49 ssize_t _bfrSurp; // surplus at start of current sweep |
51 ssize_t _beforeSweep; // count from before current sweep |
51 ssize_t _beforeSweep; // count from before current sweep |
52 ssize_t _coalBirths; // additional chunks from coalescing |
52 ssize_t _coalBirths; // additional chunks from coalescing |
53 ssize_t _coalDeaths; // loss from coalescing |
53 ssize_t _coalDeaths; // loss from coalescing |
54 ssize_t _splitBirths; // additional chunks from splitting |
54 ssize_t _splitBirths; // additional chunks from splitting |
55 ssize_t _splitDeaths; // loss from splitting |
55 ssize_t _splitDeaths; // loss from splitting |
56 size_t _returnedBytes; // number of bytes returned to list. |
56 size_t _returnedBytes; // number of bytes returned to list. |
57 public: |
57 public: |
58 void initialize() { |
58 void initialize(bool split_birth = false) { |
59 AdaptivePaddedAverage* dummy = |
59 AdaptivePaddedAverage* dummy = |
60 new (&_demand_rate_estimate) AdaptivePaddedAverage(CMS_FLSWeight, |
60 new (&_demand_rate_estimate) AdaptivePaddedAverage(CMS_FLSWeight, |
61 CMS_FLSPadding); |
61 CMS_FLSPadding); |
62 _desired = 0; |
62 _desired = 0; |
63 _coalDesired = 0; |
63 _coalDesired = 0; |
65 _bfrSurp = 0; |
65 _bfrSurp = 0; |
66 _prevSweep = 0; |
66 _prevSweep = 0; |
67 _beforeSweep = 0; |
67 _beforeSweep = 0; |
68 _coalBirths = 0; |
68 _coalBirths = 0; |
69 _coalDeaths = 0; |
69 _coalDeaths = 0; |
70 _splitBirths = 0; |
70 _splitBirths = split_birth? 1 : 0; |
71 _splitDeaths = 0; |
71 _splitDeaths = 0; |
72 _returnedBytes = 0; |
72 _returnedBytes = 0; |
73 } |
73 } |
74 |
74 |
75 AllocationStats() { |
75 AllocationStats() { |
76 initialize(); |
76 initialize(); |
77 } |
77 } |
|
78 |
78 // The rate estimate is in blocks per second. |
79 // The rate estimate is in blocks per second. |
79 void compute_desired(size_t count, |
80 void compute_desired(size_t count, |
80 float inter_sweep_current, |
81 float inter_sweep_current, |
81 float inter_sweep_estimate) { |
82 float inter_sweep_estimate, |
|
83 float intra_sweep_estimate) { |
82 // If the latest inter-sweep time is below our granularity |
84 // If the latest inter-sweep time is below our granularity |
83 // of measurement, we may call in here with |
85 // of measurement, we may call in here with |
84 // inter_sweep_current == 0. However, even for suitably small |
86 // inter_sweep_current == 0. However, even for suitably small |
85 // but non-zero inter-sweep durations, we may not trust the accuracy |
87 // but non-zero inter-sweep durations, we may not trust the accuracy |
86 // of accumulated data, since it has not been "integrated" |
88 // of accumulated data, since it has not been "integrated" |
87 // (read "low-pass-filtered") long enough, and would be |
89 // (read "low-pass-filtered") long enough, and would be |
88 // vulnerable to noisy glitches. In such cases, we |
90 // vulnerable to noisy glitches. In such cases, we |
89 // ignore the current sample and use currently available |
91 // ignore the current sample and use currently available |
90 // historical estimates. |
92 // historical estimates. |
|
93 // XXX NEEDS TO BE FIXED |
|
94 // assert(prevSweep() + splitBirths() >= splitDeaths() + (ssize_t)count, "Conservation Principle"); |
|
95 // ^^^^^^^^^^^^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ |
|
96 // "Total Stock" "Not used at this block size" |
91 if (inter_sweep_current > _threshold) { |
97 if (inter_sweep_current > _threshold) { |
92 ssize_t demand = prevSweep() - count + splitBirths() - splitDeaths(); |
98 ssize_t demand = prevSweep() - (ssize_t)count + splitBirths() - splitDeaths(); |
|
99 // XXX NEEDS TO BE FIXED |
|
100 // assert(demand >= 0, "Demand should be non-negative"); |
|
101 // Defensive: adjust for imprecision in event counting |
|
102 if (demand < 0) { |
|
103 demand = 0; |
|
104 } |
|
105 float old_rate = _demand_rate_estimate.padded_average(); |
93 float rate = ((float)demand)/inter_sweep_current; |
106 float rate = ((float)demand)/inter_sweep_current; |
94 _demand_rate_estimate.sample(rate); |
107 _demand_rate_estimate.sample(rate); |
95 _desired = (ssize_t)(_demand_rate_estimate.padded_average() |
108 float new_rate = _demand_rate_estimate.padded_average(); |
96 *inter_sweep_estimate); |
109 ssize_t old_desired = _desired; |
|
110 _desired = (ssize_t)(new_rate * (inter_sweep_estimate |
|
111 + CMSExtrapolateSweep |
|
112 ? intra_sweep_estimate |
|
113 : 0.0)); |
|
114 if (PrintFLSStatistics > 1) { |
|
115 gclog_or_tty->print_cr("demand: %d, old_rate: %f, current_rate: %f, new_rate: %f, old_desired: %d, new_desired: %d", |
|
116 demand, old_rate, rate, new_rate, old_desired, _desired); |
|
117 } |
97 } |
118 } |
98 } |
119 } |
99 |
120 |
100 ssize_t desired() const { return _desired; } |
121 ssize_t desired() const { return _desired; } |
101 void set_desired(ssize_t v) { _desired = v; } |
122 void set_desired(ssize_t v) { _desired = v; } |