diff options
| author | Bartosz Nitka <niteria@gmail.com> | 2017-05-10 04:36:52 -0700 |
|---|---|---|
| committer | Bartosz Nitka <niteria@gmail.com> | 2017-05-10 04:37:26 -0700 |
| commit | 26f509a992ebc6910ed2309b46f3f1d44efba7c9 (patch) | |
| tree | ab8b9a7f91f16046201d9957d9b015d74a6f38ac /compiler/main/GhcMake.hs | |
| parent | 22a03e7288129a165dc2cb866041185a06adb0e9 (diff) | |
| download | haskell-26f509a992ebc6910ed2309b46f3f1d44efba7c9.tar.gz | |
Efficient membership for home modules
This changes the linear lookup in a list to an efficient
lookup in an IntMap. The linear lookup effectively made
the algorithm quadratic, which for a test case that I have
(5000 modules) introduced significant slowdown.
I ran 3 experiments to estimate the impact of this:
"No-op", profiled, just `:load`: P146, `186s`
"before", profiled, `:load` followed by 10x `:r`: P147, `315s`
"after", profiled, `:load` followed by 10x `:r`: P148, `250s`
Going by the math of `(250-186)/(315-186) = 50%` this is a 2x improvement
on `:r`.
Test Plan: ./validate
Reviewers: simonmar, austin, bgamari
Reviewed By: simonmar
Subscribers: rwbarton, thomie
Differential Revision: https://phabricator.haskell.org/D3562
Diffstat (limited to 'compiler/main/GhcMake.hs')
| -rw-r--r-- | compiler/main/GhcMake.hs | 12 |
1 files changed, 7 insertions, 5 deletions
diff --git a/compiler/main/GhcMake.hs b/compiler/main/GhcMake.hs index 7cc52768c7..4d06b6e254 100644 --- a/compiler/main/GhcMake.hs +++ b/compiler/main/GhcMake.hs @@ -220,8 +220,9 @@ load' how_much mHscMessage mod_graph = do -- B.hs-boot in the module graph, but no B.hs -- The downsweep should have ensured this does not happen -- (see msDeps) - let all_home_mods = [ms_mod_name s - | s <- mod_graph, not (isBootSummary s)] + let all_home_mods = + mkUniqSet [ ms_mod_name s + | s <- mod_graph, not (isBootSummary s)] -- TODO: Figure out what the correct form of this assert is. It's violated -- when you have HsBootMerge nodes in the graph: then you'll have hs-boot -- files without corresponding hs files. @@ -236,7 +237,7 @@ load' how_much mHscMessage mod_graph = do checkHowMuch _ = id checkMod m and_then - | m `elem` all_home_mods = and_then + | m `elementOfUniqSet` all_home_mods = and_then | otherwise = do liftIO $ errorMsg dflags (text "no such module:" <+> quotes (ppr m)) @@ -656,7 +657,7 @@ unload hsc_env stable_linkables -- Unload everthing *except* 'stable_linkables' checkStability :: HomePackageTable -- HPT from last compilation -> [SCC ModSummary] -- current module graph (cyclic) - -> [ModuleName] -- all home modules + -> UniqSet ModuleName -- all home modules -> ([ModuleName], -- stableObject [ModuleName]) -- stableBCO @@ -669,7 +670,8 @@ checkStability hpt sccs all_home_mods = foldl checkSCC ([],[]) sccs where scc = flattenSCC scc0 scc_mods = map ms_mod_name scc - home_module m = m `elem` all_home_mods && m `notElem` scc_mods + home_module m = + m `elementOfUniqSet` all_home_mods && m `notElem` scc_mods scc_allimps = nub (filter home_module (concatMap ms_home_allimps scc)) -- all imports outside the current SCC, but in the home pkg |