2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
4 \section[CostCentre]{The @CostCentre@ data type}
8 CostCentre(..), CcName, IsDupdCC(..), IsCafCC(..),
9 -- All abstract except to friend: ParseIface.y
12 noCCS, subsumedCCS, currentCCS, overheadCCS, dontCareCCS,
13 noCostCentre, noCCAttached,
14 noCCSAttached, isCurrentCCS, isSubsumedCCS, currentOrSubsumedCCS,
16 mkUserCC, mkAutoCC, mkAllCafsCC,
17 mkSingletonCCS, cafifyCC, dupifyCC,
18 isCafCC, isDupdCC, isEmptyCC, isCafCCS,
23 pprCostCentreDecl, pprCostCentreStackDecl, pprCostCentreCore,
25 cmpCostCentre -- used for removing dups in a list
28 #include "HsVersions.h"
31 import Name ( UserFS, EncodedFS, encodeFS, decode,
34 import Module ( Module, pprModule, moduleUserString )
36 import Util ( thenCmp )
39 A Cost Centre Stack is something that can be attached to a closure.
42 - the current cost centre stack (CCCS)
43 - a pre-defined cost centre stack (there are several
44 pre-defined CCSs, see below).
50 | CurrentCCS -- Pinned on a let(rec)-bound
51 -- thunk/function/constructor, this says that the
52 -- cost centre to be attached to the object, when it
53 -- is allocated, is whatever is in the
54 -- current-cost-centre-stack register.
56 | SubsumedCCS -- Cost centre stack for top-level subsumed functions
57 -- (CAFs get an AllCafsCC).
58 -- Its execution costs get subsumed into the caller.
59 -- This guy is *only* ever pinned on static closures,
60 -- and is *never* the cost centre for an SCC construct.
62 | OverheadCCS -- We charge costs due to the profiling-system
63 -- doing its work to "overhead".
65 -- Objects whose CCS is "Overhead"
66 -- have their *allocation* charged to "overhead",
67 -- but have the current CCS put into the object
70 -- For example, if we transform "f g" to "let
71 -- g' = g in f g'" (so that something about
72 -- profiling works better...), then we charge
73 -- the *allocation* of g' to OverheadCCS, but
74 -- we put the cost-centre of the call to f
75 -- (i.e., current CCS) into the g' object. When
76 -- g' is entered, the CCS of the call
79 | DontCareCCS -- We need a CCS to stick in static closures
80 -- (for data), but we *don't* expect them to
81 -- accumulate any costs. But we still need
82 -- the placeholder. This CCS is it.
84 | SingletonCCS CostCentre
85 -- This is primarily for CAF cost centres, which
86 -- are attached to top-level thunks right at the
87 -- end of STG processing, before code generation.
88 -- Hence, a CAF cost centre never appears as the
89 -- argument of an _scc_.
90 -- Also, we generate these singleton CCSs statically
91 -- as part of code generation.
93 deriving (Eq, Ord) -- needed for Ord on CLabel
96 A Cost Centre is the argument of an _scc_ expression.
99 type Group = FAST_STRING -- "Group" that this CC is in; eg directory
102 = NoCostCentre -- Having this constructor avoids having
103 -- to use "Maybe CostCentre" all the time.
106 cc_name :: CcName, -- Name of the cost centre itself
107 cc_mod :: Module, -- Name of module defining this CC.
108 cc_grp :: Group, -- "Group" that this CC is in.
109 cc_is_dupd :: IsDupdCC, -- see below
110 cc_is_caf :: IsCafCC -- see below
114 cc_mod :: Module, -- Name of module defining this CC.
115 cc_grp :: Group -- "Group" that this CC is in
116 -- Again, one "big" CAF cc per module, where all
117 -- CAF costs are attributed unless the user asked for
118 -- per-individual-CAF cost attribution.
121 type CcName = EncodedFS
124 = OriginalCC -- This says how the CC is *used*. Saying that
125 | DupdCC -- it is DupdCC doesn't make it a different
126 -- CC, just that it a sub-expression which has
127 -- been moved ("dupd") into a different scope.
129 -- The point about a dupd SCC is that we don't
130 -- count entries to it, because it's not the
133 -- In the papers, it's called "SCCsub",
134 -- i.e. SCCsub CC == SCC DupdCC,
135 -- but we are trying to avoid confusion between
136 -- "subd" and "subsumed". So we call the former
139 data IsCafCC = CafCC | NotCafCC
142 WILL: Would there be any merit to recording ``I am now using a
143 cost-centre from another module''? I don't know if this would help a
144 user; it might be interesting to us to know how much computation is
145 being moved across module boundaries.
147 SIMON: Maybe later...
152 subsumedCCS = SubsumedCCS
153 currentCCS = CurrentCCS
154 overheadCCS = OverheadCCS
155 dontCareCCS = DontCareCCS
157 noCostCentre = NoCostCentre
160 Predicates on Cost-Centre Stacks
163 noCCSAttached NoCCS = True
164 noCCSAttached _ = False
166 noCCAttached NoCostCentre = True
167 noCCAttached _ = False
169 isCurrentCCS CurrentCCS = True
170 isCurrentCCS _ = False
172 isSubsumedCCS SubsumedCCS = True
173 isSubsumedCCS _ = False
175 isCafCCS (SingletonCCS cc) = isCafCC cc
178 currentOrSubsumedCCS SubsumedCCS = True
179 currentOrSubsumedCCS CurrentCCS = True
180 currentOrSubsumedCCS _ = False
183 Building cost centres
186 mkUserCC :: UserFS -> Module -> Group -> CostCentre
188 mkUserCC cc_name module_name group_name
189 = NormalCC { cc_name = encodeFS cc_name,
190 cc_mod = module_name, cc_grp = group_name,
191 cc_is_dupd = OriginalCC, cc_is_caf = NotCafCC {-might be changed-}
194 mkAutoCC :: Id -> Module -> Group -> IsCafCC -> CostCentre
196 mkAutoCC id module_name group_name is_caf
197 = NormalCC { cc_name = occNameFS (getOccName id),
198 cc_mod = module_name, cc_grp = group_name,
199 cc_is_dupd = OriginalCC, cc_is_caf = is_caf
202 mkAllCafsCC m g = AllCafsCC { cc_mod = m, cc_grp = g }
204 mkSingletonCCS :: CostCentre -> CostCentreStack
205 mkSingletonCCS cc = SingletonCCS cc
207 cafifyCC, dupifyCC :: CostCentre -> CostCentre
209 cafifyCC cc@(NormalCC {cc_is_caf = is_caf})
210 = ASSERT(not_a_caf_already is_caf)
211 cc {cc_is_caf = CafCC}
213 not_a_caf_already CafCC = False
214 not_a_caf_already _ = True
215 cafifyCC cc = pprPanic "cafifyCC" (ppr cc)
217 dupifyCC cc = cc {cc_is_dupd = DupdCC}
219 isEmptyCC, isCafCC, isDupdCC :: CostCentre -> Bool
221 isEmptyCC (NoCostCentre) = True
224 isCafCC (AllCafsCC {}) = True
225 isCafCC (NormalCC {cc_is_caf = CafCC}) = True
228 isDupdCC (NormalCC {cc_is_dupd = DupdCC}) = True
231 isSccCountCostCentre :: CostCentre -> Bool
232 -- Is this a cost-centre which records scc counts
235 isSccCountCostCentre NoCostCentre = panic "isSccCount:NoCostCentre"
237 isSccCountCostCentre cc | isCafCC cc = False
238 | isDupdCC cc = False
241 sccAbleCostCentre :: CostCentre -> Bool
242 -- Is this a cost-centre which can be sccd ?
245 sccAbleCostCentre NoCostCentre = panic "sccAbleCC:NoCostCentre"
247 sccAbleCostCentre cc | isCafCC cc = False
250 ccFromThisModule :: CostCentre -> Module -> Bool
251 ccFromThisModule cc m = cc_mod cc == m
255 instance Eq CostCentre where
256 c1 == c2 = case c1 `cmpCostCentre` c2 of { EQ -> True; _ -> False }
258 instance Ord CostCentre where
259 compare = cmpCostCentre
261 cmpCostCentre :: CostCentre -> CostCentre -> Ordering
263 cmpCostCentre (AllCafsCC {cc_mod = m1}) (AllCafsCC {cc_mod = m2}) = m1 `compare` m2
265 cmpCostCentre (NormalCC {cc_name = n1, cc_mod = m1, cc_is_caf = c1})
266 (NormalCC {cc_name = n2, cc_mod = m2, cc_is_caf = c2})
267 -- first key is module name, then we use "kinds" (which include
268 -- names) and finally the caf flag
269 = (m1 `compare` m2) `thenCmp` (n1 `compare` n2) `thenCmp` (c1 `cmp_caf` c2)
271 cmpCostCentre other_1 other_2
273 tag1 = tag_CC other_1
274 tag2 = tag_CC other_2
276 if tag1 _LT_ tag2 then LT else GT
278 tag_CC (NormalCC {}) = (ILIT(1) :: FAST_INT)
279 tag_CC (AllCafsCC {}) = ILIT(2)
281 cmp_caf NotCafCC CafCC = LT
282 cmp_caf NotCafCC NotCafCC = EQ
283 cmp_caf CafCC CafCC = EQ
284 cmp_caf CafCC NotCafCC = GT
287 -----------------------------------------------------------------------------
288 Printing Cost Centre Stacks.
290 There are two ways to print a CCS:
292 - for debugging output (i.e. -ddump-whatever),
296 instance Outputable CostCentreStack where
297 ppr ccs = case ccs of
298 NoCCS -> ptext SLIT("NO_CCS")
299 CurrentCCS -> ptext SLIT("CCCS")
300 OverheadCCS -> ptext SLIT("CCS_OVERHEAD")
301 DontCareCCS -> ptext SLIT("CCS_DONTZuCARE")
302 SubsumedCCS -> ptext SLIT("CCS_SUBSUMED")
303 SingletonCCS cc -> ptext SLIT("CCS_") <> ppr cc
305 pprCostCentreStackDecl :: CostCentreStack -> SDoc
306 pprCostCentreStackDecl ccs@(SingletonCCS cc)
308 is_subsumed = ccSubsumed cc
310 hcat [ ptext SLIT("CCS_DECLARE"), char '(',
311 ppr ccs, comma, -- better be codeStyle
312 ppCostCentreLbl cc, comma,
313 ptext is_subsumed, comma,
314 empty, -- Now always externally visible
318 pprCostCentreStackDecl ccs
319 = pprPanic "pprCostCentreStackDecl: " (ppr ccs)
322 -----------------------------------------------------------------------------
323 Printing Cost Centres.
325 There are several different ways in which we might want to print a
328 - the name of the cost centre, for profiling output (a C string)
329 - the label, i.e. C label for cost centre in .hc file.
330 - the debugging name, for output in -ddump things
331 - the interface name, for printing in _scc_ exprs in iface files.
333 The last 3 are derived from costCentreStr below. The first is given
337 instance Outputable CostCentre where
338 ppr cc = getPprStyle $ \ sty ->
340 then ppCostCentreLbl cc
341 else text (costCentreUserName cc)
343 -- Printing in an interface file or in Core generally
344 pprCostCentreCore (AllCafsCC {cc_mod = m, cc_grp = g})
345 = text "__sccC" <+> braces (pprModule m <+> doubleQuotes (ptext g))
346 pprCostCentreCore (NormalCC {cc_name = n, cc_mod = m, cc_grp = g,
347 cc_is_caf = caf, cc_is_dupd = dup})
348 = text "__scc" <+> braces (hsep [
351 doubleQuotes (ptext g),
356 pp_dup DupdCC = char '!'
359 pp_caf CafCC = text "__C"
363 -- Printing as a C label
364 ppCostCentreLbl (NoCostCentre) = text "CC_NONE"
365 ppCostCentreLbl (AllCafsCC {cc_mod = m}) = text "CC_CAFs_" <> pprModule m
366 ppCostCentreLbl (NormalCC {cc_name = n, cc_mod = m}) = text "CC_" <> pprModule m <> ptext n
368 -- This is the name to go in the user-displayed string,
369 -- recorded in the cost centre declaration
370 costCentreUserName (NoCostCentre) = "NO_CC"
371 costCentreUserName (AllCafsCC {}) = "CAFs_in_..."
372 costCentreUserName (NormalCC {cc_name = name, cc_is_caf = is_caf})
373 = case is_caf of { CafCC -> "CAF:"; _ -> "" } ++ decode (_UNPK_ name)
376 Cost Centre Declarations
380 pprCostCentreDecl is_local (NoCostCentre)
381 = panic "pprCostCentreDecl: no cost centre!"
383 pprCostCentreDecl is_local cc
386 ptext SLIT("CC_DECLARE"),char '(',
388 doubleQuotes (text (costCentreUserName cc)), comma,
389 doubleQuotes (text (moduleUserString mod_name)), comma,
390 doubleQuotes (ptext grp_name), comma,
391 ptext is_subsumed, comma,
392 empty, -- Now always externally visible
395 hcat [ ptext SLIT("CC_EXTERN"),char '(', cc_ident, text ");" ]
397 cc_ident = ppCostCentreLbl cc
400 is_subsumed = ccSubsumed cc
402 ccSubsumed :: CostCentre -> FAST_STRING -- subsumed value
403 ccSubsumed cc | isCafCC cc = SLIT("CC_IS_CAF")
404 | otherwise = SLIT("CC_IS_BORING")