Re: [squeak-dev] Re: Mac VM hanging

On 28.06.2011, at 16:58, Bob Arning wrote:

David,

I have narrowed it down further. The problem is an interaction between:

• my code
• MessageTally
• some GC tweaks I was using (see below)

If I don't use MessageTally, everything runs fine. If I don't use the GC tweaks, everything runs fine. If I use them in combination, then Squeak grinds to a halt somewhere short of the end of my code (which would normally take a few minutes). I guess this give me a workaround, but if any of the numbers in the code below are known to be a problem, I'll mention it on the seaside list.

I've been using this for a specific application:

vmParameterAt: 5 put: 16000; "do an incremental GC after this many allocations" vmParameterAt: 6 put: 32000; "tenure when more than this many objects survive the GC" vmParameterAt: 24 put: 16*1024*1024; "when growing object memory, allocate this much extra space" vmParameterAt: 25 put: 8*1024*1024. "when more than this much is free, shrink object memory"

There are two main differences: the incremental GC runs more often, and I did not enable the bias-to-grow.

- Bert -

Cheers, Bob

initializeMemorySettingsProfileSeaside "Initialize the memory and GC settings to be more in line with Seaside requirements"

   "The following settings affect the rate incremental GCs and

tenuring"

   "Limit incremental GC activity to run every 40k allocations"
   self vmParameterAt: 5 put: 100000. "allocations between GCs

(default: 4000)" "Limit tenuring threshold to only tenure w/ > 35k survivors" self vmParameterAt: 6 put: 35000. "tenuring threshold (default: 2000)"

   "These settings affect overall memory usage"

   "Only give memory back to the OS when we have more than 16MB free"
   self vmParameterAt: 24 put: 16*1024*1024. "default 8MB"
   "Try to keep 8MB headroom at all times"
   self vmParameterAt: 25 put: 8*1024*1024. "default 4MB"

   "These settings describe what to do when we're close to running out

of free space"

   "Tell the VM that we'd rather grow than spinning in tight GC loops"
   self setGCBiasToGrow: 1. "default: false"
   "Tell the VM to do a fullGC for good measure if the above growth

exceeded 16MB" self setGCBiasToGrowGCLimit: 16*1024*1024. "default: 0"

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