----- On Jun 14, 2018, at 10:00 AM, Florian Weimer fweimer@xxxxxxxxxx wrote:
On 06/14/2018 03:49 PM, Pavel Machek wrote:
- rseq_preempt(): on preemption, the scheduler sets the TIF_NOTIFY_RESUME thread
flag, so rseq_handle_notify_resume() can check whether it's in a rseq critical
section when returning to user-space,
- rseq_signal_deliver(): on signal delivery, rseq_handle_notify_resume() checks
whether it's in a rseq critical section,
- rseq_migrate: on migration, the scheduler sets TIF_NOTIFY_RESUME as well,
Yes, this is not likely to be noticeable.
But the proposal wanted to add a syscall to thread creation, right?
And I believe that may be noticeable.
Fair point! Do we have a standard benchmark that would stress this ?
Web server performance benchmarks basically test clone() performance
in many cases.
Isn't that fork? I expect that the rseq arena is inherited on fork and
fork-type clone, otherwise it's going to be painful.
On fork or clone creating a new process, the rseq tls area is inherited
from the thread that does the fork syscall.
On creation of a new thread with clone, there is no such inheritance.