Commit 4b195711 authored by Simon Peyton Jones's avatar Simon Peyton Jones

Add notes about nofib

parent 890caa40
......@@ -13,6 +13,11 @@ whereas it didn't before. So allocations go up a bit.
Imaginary suite
integrate1D is strict in its second argument 'u', but it also passes 'u' to
function 'f'. Hence it now does some reboxing, which pushes up allocation
......@@ -215,6 +220,11 @@ Lambda
This program shows the cost of the non-eta-expanded lambdas that arise from
a state monad.
check_perim's several calls to point_colour lead to opportunities for CSE
which may be more or less well taken.
Relies heavily on having a specialised version of Complex.magnitude
......@@ -339,19 +349,36 @@ Sphere also does 60,000 calls to hPutStr, so I/O plays a major role. Currently
this I/O does a *lot* of allocation, much of it since the adddition of thread-safety.
Does a lot of IO.readFile.
Does a lot of IO.readFile. In GHC.IO.Encoding.UTF8 the demand
analyser sees a strict function with type
a_s1gj :: GHC.IO.Buffer.Buffer GHC.Word.Word8
-> GHC.IO.Buffer.Buffer GHC.Types.Char
-> GHC.Prim.State# GHC.Prim.RealWorld
-> (# GHC.Prim.State# GHC.Prim.RealWorld,
GHC.IO.Buffer.Buffer GHC.Word.Word8,
GHC.IO.Buffer.Buffer GHC.Types.Char) #)
Unboxing both Buffer arguments makes a HUGE difference (halves
allocation); but that makes the worker function have 12 arguments. A
good reason for unboxing even if the worker gets a lot of args.
Same issue with GHC.IO.Encoding.UTF8 as treejoin
Real suite
Same issue with GHC.IO.Encoding.UTF8 as treejoin
Uses appendFile repeatedly rather than opening the output file once,
which leads to numerous file opens/closes. Allocations will rise with
the new I/O subsystem in 5.02 because the I/O buffer will be
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