Re: [Qemu-devel] [RFC][PATCH] Register Linux dyntick timer as per-thread signal

[Ingo Molnar]

* Jan Kiszka <address@hidden> wrote:

> Ingo Molnar pointed out that sending the timer signal to the whole
> process, just blocking it everywhere, is suboptimal with an increasing
> number of threads. QEMU is using this pattern so far.
> 
> But Linux provides a (non-portable) way to restrict the signal to a
> single thread: Use SIGEV_THREAD_ID unless we are forced to emulate
> signalfd via an additional thread. That case could theoretically be
> optimized as well, but it doesn't look worth bothering.

Would be nice to mention it in the changelog that the context and 
motivation for my remark was a patch sent for tools/kvm/ by Asias He:

  kvm tools: Block SIGALRM for vcpu thread using sig_block() helper

Thanks,

        Ingo