[Vm-dev] Maximum value of -stackpages VM parameter?
Eliot Miranda
eliot.miranda at gmail.com
Mon Jun 12 20:42:52 UTC 2017
Hi Phil,
> On Jun 12, 2017, at 12:50 PM, Phil B <pbpublist at gmail.com> wrote:
>
> In trying to troubleshoot an issue, I needed to bump up the stackpages parameter. On 64-bit Linux, a value of 600 worked but 1000 segfaulted so I was just wondering what the limit(s) are for it?
There are no explicit limits. The set fault you're seeing is as a result of the stack pages being allocated on the c stack. When the number is high the stack overflows and boom.
A word to the wise: too high a value and scavenging performance falls (stack pages are implicitly roots into new space), and become performance falls (all activations in stack space are scanned post become to avoid a read barrier on inst var fetch).
The default value was 192, a value chosen to exceed qwaq server process usage, but both at Cadence and in Spur profiling we found that was not a good value and pulled it back to 64 (IIRC).
I'm curious as to why are you exploring such high values.
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