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sim: posix: add platform-specific timer handling for macOS and Linux #18331

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sim: posix: add platform-specific timer handling for macOS and Linux #18331

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5f6e8b2
sim: posix: use setitimer on Darwin, POSIX timers on Linux
aditya0yadav Feb 3, 2026
151aaeb
Merge branch 'apache:master' into master
aditya0yadav Feb 3, 2026
d82561b
now setimer is shared between linux and macos
aditya0yadav Feb 4, 2026
6603580
fix the word problem
aditya0yadav Feb 4, 2026
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1 change: 1 addition & 0 deletions arch/sim/src/sim/posix/sim_hostmisc.c
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Original file line number Diff line number Diff line change
Expand Up @@ -24,6 +24,7 @@
* Included Files
****************************************************************************/

#include <signal.h>
#include <errno.h>
#include <limits.h>
#include <stdio.h>
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47 changes: 19 additions & 28 deletions arch/sim/src/sim/posix/sim_hosttime.c
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Original file line number Diff line number Diff line change
@@ -1,6 +1,8 @@
/****************************************************************************
* arch/sim/src/sim/posix/sim_hosttime.c
*
* SPDX-License-Identifier: Apache-2.0
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
Expand Down Expand Up @@ -36,8 +38,9 @@
* Private Data
****************************************************************************/

/* Start time of the simulation in nanoseconds (monotonic clock) */

static uint64_t g_start;
static timer_t g_timer;

/****************************************************************************
* Public Functions
Expand All @@ -50,18 +53,11 @@ static timer_t g_timer;
int host_inittimer(void)
{
struct timespec tp;
struct sigevent sigev =
{
0
};

clock_gettime(CLOCK_MONOTONIC, &tp);

g_start = 1000000000ull * tp.tv_sec + tp.tv_nsec;
sigev.sigev_notify = SIGEV_SIGNAL;
sigev.sigev_signo = SIGALRM;

return timer_create(CLOCK_MONOTONIC, &sigev, &g_timer);
return 0;
}

/****************************************************************************
Expand Down Expand Up @@ -105,33 +101,28 @@ void host_sleepuntil(uint64_t nsec)

/****************************************************************************
* Name: host_settimer
*
* Description:
* Set up a timer to send periodic signals.
*
* Input Parameters:
* nsec - timer expire time
*
* Returned Value:
* On success, (0) zero value is returned, otherwise a negative value.
*
****************************************************************************/

int host_settimer(uint64_t nsec)
{
struct itimerspec tspec =
{
0
};
struct itimerval it;
uint64_t now;
uint64_t usec;

now = host_gettime(false);

usec = (nsec <= now) ? 1 : (nsec - now) / 1000;
usec = (usec == 0) ? 1 : usec;

/* Convert to microseconds and set minimum timer to 1 microsecond. */
it.it_value.tv_sec = usec / 1000000;
it.it_value.tv_usec = usec % 1000000;

nsec += g_start;
/* One-shot timer */

tspec.it_value.tv_sec = nsec / 1000000000;
tspec.it_value.tv_nsec = nsec % 1000000000;
it.it_interval.tv_sec = 0;
it.it_interval.tv_usec = 0;

return timer_settime(g_timer, TIMER_ABSTIME, &tspec, NULL);
return setitimer(ITIMER_REAL, &it, NULL);
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@xiaoxiang781216 xiaoxiang781216 Feb 3, 2026 •
edited
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why not use setitimer on Linux too? https://linux.die.net/man/2/setitimer

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@aditya0yadav aditya0yadav Feb 3, 2026

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Because linux has a better api : timer_create() + timer_settime()
in macos , we have to use that time_create exist but unreliable and uncompleted and time_settime() is not properly supported

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@xiaoxiang781216 xiaoxiang781216 Feb 3, 2026

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it's better to go the same code path if we can, so don't need double the test effort.

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@aditya0yadav aditya0yadav Feb 3, 2026

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@xiaoxiang781216 Ok i will do that
Any suggestion about linker
for to use sim in macos , we need to disable the gcov

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@aditya0yadav aditya0yadav Feb 4, 2026

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@xiaoxiang781216 now set timer is being shared bet linux and macOS

}

/****************************************************************************
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