firefly:
I added Don's three benchmarks and redid all my benchmarks with: ghc 6.6.1 ghc 6.8.2 ghc 6.8.2 + bytestring 0.9.0.2 ghc 6.9.20071119 ghc 6.9.20071119 + bytestring 0.9.0.2 ghc head-as-of-yesterday-around-noon ghc head-as-of-yesterday-around-noon + bytestring 0.9.0.2
One thing that shows up very clearly in the graphs is that the memory situation is bad and that Don's recent fix only really solves the problem on 6.8.2, not on head.
Can you pinpoint specific programs, with either ghc 6.8.2 or head, that allocate too much? That's likely to be a library issue that I can address in ByteString. I'd need the source program, whether it is with ghc 6.8.2 or ghc head, and what compiler flags (and input size). Low level loop/performance issues go to SimonM (i.e. if its allocating fine, the core is perfect, but just too slow). -- Don