Skip to content

[3.10] bpo-21302: Add clock_nanosleep() implementation for time.sleep() in Linux #28077

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Closed
wants to merge 1 commit into from
Closed

[3.10] bpo-21302: Add clock_nanosleep() implementation for time.sleep() in Linux #28077

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
23 changes: 22 additions & 1 deletion Modules/timemodule.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -60,6 +60,10 @@
# define HAVE_CLOCK_GETTIME_RUNTIME 1
#endif

#if (!defined(MS_WINDOWS) && defined(__linux__) && defined(_POSIX_VERSION)) && (_POSIX_VERSION >= 200112L)
# define HAVE_CLOCK_NANOSLEEP 1
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I would prefer a check in configure.

#endif

#define SEC_TO_NS (1000 * 1000 * 1000)

/* Forward declarations */
Expand Down Expand Up @@ -2044,6 +2048,23 @@ PyInit_time(void)
return PyModuleDef_Init(&timemodule);
}

#ifndef MS_WINDOWS
static int
sleep_unix(struct timeval timeout)
{
int ret = 0;
#ifdef HAVE_CLOCK_NANOSLEEP
struct timespec request;
request.tv_sec = timeout.tv_sec;
request.tv_nsec = (long)(timeout.tv_usec) * 1000;
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

This line makes me sad. The caller uses nanosecond resolution (10^-9), then _PyTime_AsTimeval() truncates to microsecond resolution (10^-6).

I would prefer to inline this code in pysleep() and avoid _PyTime_AsTimeval() for the clock_nanosleep() code path.

ret = clock_nanosleep(CLOCK_MONOTONIC, 0, &request, NULL);
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I would prefer to avoid computing the relative 'timeout' value, but just pass 'deadline' absolute time since it's already computed: use flags=TIMER_ABSTIME.

#else
ret = select(0, (fd_set *)0, (fd_set *)0, (fd_set *)0, &timeout);
#endif
return ret;
}
#endif

/* Implement pysleep() for various platforms.
When interrupted (or when another error occurs), return -1 and
set an exception; else return 0. */
Expand Down Expand Up @@ -2073,7 +2094,7 @@ pysleep(_PyTime_t secs)
return -1;

Py_BEGIN_ALLOW_THREADS
err = select(0, (fd_set *)0, (fd_set *)0, (fd_set *)0, &timeout);
err = sleep_unix(timeout);
Py_END_ALLOW_THREADS

if (err == 0)
Expand Down