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| author | Simon Marlow <marlowsd@gmail.com> | 2011-11-28 16:48:43 +0000 |
|---|---|---|
| committer | Simon Marlow <marlowsd@gmail.com> | 2011-11-29 12:21:18 +0000 |
| commit | 50de6034343abc93a7b01daccff34121042c0e7c (patch) | |
| tree | 24496a5fc6bc39c6baaa574608e53c5d76c169f6 /compiler/cmm/CmmExpr.hs | |
| parent | 1c2b838131134d44004dfdff18c302131478390d (diff) | |
| download | haskell-50de6034343abc93a7b01daccff34121042c0e7c.tar.gz | |
Make profiling work with multiple capabilities (+RTS -N)
This means that both time and heap profiling work for parallel
programs. Main internal changes:
- CCCS is no longer a global variable; it is now another
pseudo-register in the StgRegTable struct. Thus every
Capability has its own CCCS.
- There is a new built-in CCS called "IDLE", which records ticks for
Capabilities in the idle state. If you profile a single-threaded
program with +RTS -N2, you'll see about 50% of time in "IDLE".
- There is appropriate locking in rts/Profiling.c to protect the
shared cost-centre-stack data structures.
This patch does enough to get it working, I have cut one big corner:
the cost-centre-stack data structure is still shared amongst all
Capabilities, which means that multiple Capabilities will race when
updating the "allocations" and "entries" fields of a CCS. Not only
does this give unpredictable results, but it runs very slowly due to
cache line bouncing.
It is strongly recommended that you use -fno-prof-count-entries to
disable the "entries" count when profiling parallel programs. (I shall
add a note to this effect to the docs).
Diffstat (limited to 'compiler/cmm/CmmExpr.hs')
| -rw-r--r-- | compiler/cmm/CmmExpr.hs | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/compiler/cmm/CmmExpr.hs b/compiler/cmm/CmmExpr.hs index ef97a82aa9..885639b874 100644 --- a/compiler/cmm/CmmExpr.hs +++ b/compiler/cmm/CmmExpr.hs @@ -343,7 +343,8 @@ data GlobalReg | SpLim -- Stack limit | Hp -- Heap ptr; points to last occupied heap location. | HpLim -- Heap limit register - | CurrentTSO -- pointer to current thread's TSO + | CCCS -- Current cost-centre stack + | CurrentTSO -- pointer to current thread's TSO | CurrentNursery -- pointer to allocation area | HpAlloc -- allocation count for heap check failure @@ -395,6 +396,7 @@ instance Ord GlobalReg where compare SpLim SpLim = EQ compare Hp Hp = EQ compare HpLim HpLim = EQ + compare CCCS CCCS = EQ compare CurrentTSO CurrentTSO = EQ compare CurrentNursery CurrentNursery = EQ compare HpAlloc HpAlloc = EQ @@ -419,6 +421,8 @@ instance Ord GlobalReg where compare _ Hp = GT compare HpLim _ = LT compare _ HpLim = GT + compare CCCS _ = LT + compare _ CCCS = GT compare CurrentTSO _ = LT compare _ CurrentTSO = GT compare CurrentNursery _ = LT |