Re: [PATCH v2] signals: Avoid unnecessary taking of sighand->siglock

[Waiman Long]

On 09/23/2016 03:43 PM, Stas Sergeev wrote:
> 23.09.2016 19:56, Waiman Long ÐÐÑÐÑ:
> > When running certain database workload on a high-end system with many
> > CPUs, it was found that spinlock contention in the sigprocmask syscalls
> > became a significant portion of the overall CPU cycles as shown below.
> Hi, I was recently facing the same problem, and my solution
> was to extract swapcontext() from libtask - it has better semantic
> and does not do sigprocmask. How much you hack sigprocmask,
> it is still faster to just not call it at all.
> Alternatively, perhaps the speed-up can be achieved if the
> current mask is exported to glibc via vdso.
> Just my 2 cents.

The problem was in a third-party software not under our control. I am 
just doing my part to try to alleviate the problem from the kernel's 
perspective.

Cheers,
Longman