Re: igc, macOS avoiding signals

[Helmut Eller]

On Mon, Dec 30 2024, Pip Cet wrote:

> IMHO, we now have three solutions that are still in the running (my
> order of preference):
>
> 1. keep the current code and special-case some signals which are needed
> for user responsiveness
> 2. use the signal serialization thread you proposed
> 3. use an allocation thread, but keep SIGSEGV on the main thread

I think this is missing:

4. add callbacks to ArenaEnter/ArenaLeave to block/unblock signals

Perhaps add 5. (or make it a variant of 1)

5. special-case some performance critical handlers and simplify all
   others so that they are obviously harmless.

   The SIGIO handler is an example for a harmless signal handler.
   handle_alarm_signal seems harmless too.

   handle_interrupt_signal is definitely not harmless, but may not be
   preformance critical.

   So far SIGPROF seems to be the only performance cortical handler.
   
Helmut