Motivation:

Starting from Netty-4.1.76, scheduled tasks may be delayed or missed in
applications that are regularly interrupted by signals.

Modification:

Use decaying timeout in epoll_wait retry loop - measure the time spent
in an interrupted syscall, and reduce the remaining timeout value for
subsequence calls.

Result:

Scheduled tasks fired off at correct time. Reproduced and verified with
an example application -
https://github.com/dsidorov/netty-epoll-timer-example

Fixes #14368.

---------

Co-authored-by: Denis Sidorov <sidorovd@amazon.com>

Motivation:

Starting from Netty-4.1.76, scheduled tasks may be delayed or missed in
applications that are regularly interrupted by signals.

Modification:

Use decaying timeout in epoll_wait retry loop - measure the time spent
in an interrupted syscall, and reduce the remaining timeout value for
subsequence calls.

Result:

Scheduled tasks fired off at correct time. Reproduced and verified with
an example application -
https://github.com/dsidorov/netty-epoll-timer-example

Fixes #14368.

---------

Co-authored-by: Denis Sidorov <sidorovd@amazon.com>

The deadline computation in netty_epoll_wait divided tv_nsec by 1000
(producing microseconds) instead of 1000000 (producing milliseconds).
Since all other values in the expression are in milliseconds, this
caused the nanosecond component to be ~1000x too large, corrupting
the deadline and defeating the decaying timeout logic introduced in
PR netty#14425.

The deadline computation in netty_epoll_wait divided tv_nsec by 1000
(producing microseconds) instead of 1000000 (producing milliseconds).
Since all other values in the expression are in milliseconds, this
caused the nanosecond component to be ~1000x too large, corrupting
the deadline and defeating the decaying timeout logic introduced in
PR netty#14425.