#4421: Compilation performance regression
---------------------------------+------------------------------------------
Reporter: simonmar | Owner:
Type: bug | Status: new
Priority: highest | Milestone: 7.0.1
Component: Compiler | Version: 6.12.3
Keywords: | Testcase:
Blockedby: | Difficulty:
Os: Unknown/Multiple | Blocking:
Architecture: Unknown/Multiple | Failure: None/Unknown
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This patch
{{{
Tue Oct 19 08:45:52 PDT 2010 Ian Lynagh <[email protected]>
* seq the unfolding in setUnfoldingInfo
Contrary to the comment, for the module in #4367 at least, it is a big
improvement. Without it we get a huge spike of drag.
}}}
Had a big impact on compile times, we probably need to address the leak
some other way. HEAD before the patch, compiling Cabal with -O:
{{{
45,244,270,096 bytes allocated in the heap
7,967,118,472 bytes copied during GC
162,341,616 bytes maximum residency (40 sample(s))
21,318,984 bytes maximum slop
472 MB total memory in use (0 MB lost due to fragmentation)
Generation 0: 85611 collections, 0 parallel, 25.94s, 25.95s elapsed
Generation 1: 40 collections, 0 parallel, 10.13s, 10.14s elapsed
INIT time 0.00s ( 0.00s elapsed)
MUT time 42.92s ( 45.75s elapsed)
GC time 36.07s ( 36.09s elapsed)
EXIT time 0.00s ( 0.00s elapsed)
Total time 78.99s ( 81.84s elapsed)
}}}
and after the patch:
{{{
67,912,400,256 bytes allocated in the heap
10,084,908,352 bytes copied during GC
88,734,416 bytes maximum residency (67 sample(s))
18,782,600 bytes maximum slop
268 MB total memory in use (0 MB lost due to fragmentation)
INIT time 0.00s ( 0.00s elapsed)
MUT time 57.62s ( 60.52s elapsed)
GC time 47.92s ( 47.96s elapsed)
EXIT time 0.00s ( 0.00s elapsed)
Total time 105.55s (108.48s elapsed)
}}}
overall space usage is much better (268M vs. 472M), but allocations and
total time are much worse.
Results for 6.12.3:
{{{
26,404,281,056 bytes allocated in the heap
6,533,229,296 bytes copied during GC
91,037,368 bytes maximum residency (49 sample(s))
17,657,552 bytes maximum slop
271 MB total memory in use (4 MB lost due to fragmentation)
INIT time 0.00s ( 0.00s elapsed)
MUT time 34.32s ( 36.88s elapsed)
GC time 24.46s ( 25.25s elapsed)
EXIT time 0.00s ( 0.00s elapsed)
Total time 58.78s ( 62.13s elapsed)
}}}
and for STABLE (before the offending patch):
{{{
32,812,959,504 bytes allocated in the heap
7,358,388,512 bytes copied during GC
159,592,480 bytes maximum residency (39 sample(s))
20,403,664 bytes maximum slop
466 MB total memory in use (0 MB lost due to fragmentation)
INIT time 0.00s ( 0.00s elapsed)
MUT time 38.59s ( 41.45s elapsed)
GC time 30.72s ( 30.74s elapsed)
EXIT time 0.00s ( 0.00s elapsed)
Total time 69.32s ( 72.19s elapsed)
}}}
HEAD is worse than STABLE right now, probably due to the containers
package changes.
STABLE has still regressed relative to 6.12.3, though.
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/4421>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler
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