128Mb of 10ns SODIMM arrived this morning, and was fitted with#

Wed, 23 Jan 2002 23:55:33 +0000

128Mb of 10ns SODIMM arrived this morning, and was fitted with assistance from the instructions at http://www.theimac.com/ram_vram_steps.shtml - completely painless. Suddenly my GC speed increased from 1Mb/second to something over 20.

Armed with that, was able to fix yesterday's problem. It was dying when doing a GC that had been stalled during a pseudo-atomic section. This turns out to be due to a disagreement between glibc and the kernel about the size of sigsett; given that the kernel puts its idea ofa sigsett onto my stack, it seems a trifle unsporting to arrange headers so that i only get access to the glibc version - especially when I then want to change this information and merrily trash the following (1024-64)/32 words as well because glibc thinks I have 1024 signals. Hate hate despise despise.

Next problem is GCs during assembly routines: if we use the `raw' return convention to call a routine that GC might occur during (which actually, horrible thought, is any of them, if they get interrupted and the signal handler conses), the GC does not adjust the link register (it's unboxed, which makes it difficult to decide what to update it to) so we end up returning to our old address instead of the new one. The only reliable fix for this, I think, is (1) don't use the `raw' return convention anywhere, or (2) figure out some way to adjust lr in GC. That's going to involve finding the caller's code vector and fiddling with offsets in much the same way we fiddle with our own code vector to calculate PC