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Fix binary tune base case and add approximation after access to

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previously queried measure that is still missing.
This commit is contained in:
Andrey Kotlarski 2014-09-05 13:52:46 +03:00
parent e8bb4a91da
commit facdb9f6bc
1 changed files with 61 additions and 33 deletions
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94
vlf-tune.el
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@ -100,7 +100,7 @@ but don't change batch size. If t, measure and change."
(defun vlf-tune-initialize-measurement ()
"Initialize measurement vector."
(make-vector (1- (/ vlf-tune-max vlf-tune-step)) '(0 . 0)))
(make-vector (/ vlf-tune-max vlf-tune-step) '(0 . 0)))
(defmacro vlf-tune-add-measurement (vec size time)
"Add at an appropriate position in VEC new SIZE TIME measurement.
@ -108,9 +108,12 @@ VEC is a vector of (mean time . count) elements ordered by size."
`(when (and vlf-tune-enabled (not (zerop ,size)))
(or ,vec (setq ,vec (vlf-tune-initialize-measurement)))
(let* ((idx (vlf-tune-closest-index ,size))
(existing (aref ,vec idx)))
(existing (aref ,vec idx))
(existing-val (car existing)))
(aset ,vec idx (let ((count (1+ (cdr existing)))) ;recalculate mean
(cons (/ (+ (* (1- count) (car existing))
(cons (/ (+ (* (1- count)
(if (= existing-val -1) 0
existing-val))
(/ ,size ,time))
count)
count))))))
@ -169,29 +172,51 @@ SIZE is number of bytes that are saved."
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;; tuning
(defun vlf-tune-approximate-nearby (vec index)
"VEC has value for INDEX, approximate to closest available."
(let ((val 0)
(left-idx (1- index))
(right-idx (1+ index))
(max (length vec)))
(while (and (zerop val) (or (<= 0 left-idx)
(< right-idx max)))
(when (<= 0 left-idx)
(setq val (car (aref vec left-idx)))
(if (and (not (zerop val)) (/= val -1))
(setq val (/ (* val (1+ index))
(1+ left-idx)))))
(if (< right-idx max)
(let ((right (car (aref vec left-idx))))
(if (and (not (zerop right)) (/= right -1))
(setq right (/ (* right (1+ index))
(1+ right-idx))
val (if (zerop val)
right
(/ (+ val right) 2)))))))
val))
(defmacro vlf-tune-approximate (vec index)
"Unless VEC has value for INDEX, approximate to closest available."
`(if ,vec
(let ((val (car (aref ,vec ,index))))
(cond ((zerop val)
(aset ,vec ,index '(-1 . 0)) ;mark element as tried once
0)
((= val -1) ;index has been tried before, yet still no value
(vlf-tune-approximate-nearby ,vec ,index))
(t val)))))
(defun vlf-tune-assess (type coef index)
"Get measurement value according to TYPE, COEF and INDEX."
(* coef (or (cond ((eq type :insert)
(if vlf-tune-insert-bps
(car (aref vlf-tune-insert-bps index))))
(vlf-tune-approximate vlf-tune-insert-bps index))
((eq type :raw)
(if vlf-tune-insert-raw-bps
(car (aref vlf-tune-insert-raw-bps index))))
((eq type :encode) ;encode size is less than batch size
(if vlf-tune-encode-bps
(let ((closest-idx index)
(val (car (aref vlf-tune-encode-bps
index))))
(while (and (zerop val)
(not (zerop closest-idx)))
(setq closest-idx (1- closest-idx)
val (car (aref vlf-tune-encode-bps
closest-idx))))
(/ (* val (1+ index)) ;approximate
(1+ closest-idx)))))
(vlf-tune-approximate vlf-tune-insert-raw-bps
index))
((eq type :encode)
(vlf-tune-approximate vlf-tune-encode-bps index))
((eq type :write)
(if vlf-tune-write-bps
(car (aref vlf-tune-write-bps index))))
(vlf-tune-approximate vlf-tune-write-bps index))
((eq type :hexl)
(if vlf-tune-hexl-bps
(car (aref vlf-tune-hexl-bps index))))
@ -253,18 +278,21 @@ INDEX if given, specifies search independent of current batch size."
"Adjust `vlf-batch-size' to optimal value using binary search, \
optimizing over TYPES.
MIN and MAX specify interval of indexes to search."
(let* ((left-idx (round (+ (* 3 min) max) 4))
(left (vlf-tune-score types left-idx)))
(if left
(let* ((right-idx (round (+ min (* 3 max)) 4))
(right (vlf-tune-score types right-idx)))
(cond ((null right)
(setq vlf-batch-size (* (1+ right-idx)
vlf-tune-step)))
((< left right)
(vlf-tune-binary types (/ (+ 1 max min) 2) max))
(t (vlf-tune-binary types min (/ (+ max min) 2)))))
(setq vlf-batch-size (* (1+ left-idx) vlf-tune-step)))))
(let ((sum (+ min max)))
(if (< (- max min) 3)
(vlf-tune-conservative types (/ sum 2))
(let* ((left-idx (round (+ sum (* 2 min)) 4))
(left (vlf-tune-score types left-idx)))
(if left
(let* ((right-idx (round (+ sum (* 2 max)) 4))
(right (vlf-tune-score types right-idx)))
(cond ((null right)
(setq vlf-batch-size (* (1+ right-idx)
vlf-tune-step)))
((< left right)
(vlf-tune-binary types (/ (1+ sum) 2) max))
(t (vlf-tune-binary types min (/ sum 2)))))
(setq vlf-batch-size (* (1+ left-idx) vlf-tune-step)))))))
(defun vlf-tune-linear (types max-idx)
"Adjust `vlf-batch-size' to optimal value using linear search, \