Hi,

Thanks for the reply. I'm beginning to see just how much work it would
be. A simple global search for static variables just doesn't get close
to the amount of work really involved. There's a lot of data not
explicitly marked static (including, as you say, variables defined in
macros). There's probably weeks if not months of work here.

I also think it will be hard to accurately estimate the performance
impact of TLS without actually doing all the work, because until all
the modules are converted, we probably won't know exactly which call
sites would need to access the TLS data. A starting point might be a
throwaway prototype that just compares direct static data access to
TLS access. It would be hard to simulate appropriate cache-usage
patterns in such a test though. I'm also not sure exactly how to read
the results: without knowing the potential call-sites in the V8 code,
it would be difficult to say exactly how fast one TLS access would
need to be compared to the existing static access. Then there's the
question of whether all platforms would have similarly fast TLS
access.

Anyway, this (V8 with this patch) would still be my preferred solution
overall, but it's probably not practical for me to put this amount of
work in at this time :-(

Best Regards,
Steve

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