I/O overhead in opening and writing files
wren ng thornton
wren at freegeek.org
Tue Aug 28 05:24:21 CEST 2012
On 8/27/12 6:25 PM, J Baptist wrote:
> Using ByteStrings and the C calls does indeed speed things up a bit, but not much.
> real 0m6.053suser 0m1.480ssys 0m4.550s
> For your interest:The original version (with Strings and openFile): http://hpaste.org/73803Faster (with Strings and c_open): http://hpaste.org/73802Even faster (with ByteStrings and c_open): http://hpaste.org/73801
> The problem may be that even with ByteStrings, we are stuck using show, and thus Strings, at some point.
Don't use Show.
Show is only there for printing things at the REPL and has no place in
performance-centric code. The bytestring-lexing package has efficient
functions for rendering integral numbers into ByteStrings. And there
are a number of other efficient ByteString renderers as well, such as
 Albeit, they haven't been hyper-aggressively optimized (cf.,
readDecimal), but that's because I haven't run into the need for doing
so. If you can demonstrate a real need, I'm willing to spend some time
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