/*
* Copyright (c) 2016 Apple Inc. All rights reserved.
*
* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
*
* This file contains Original Code and/or Modifications of Original Code
* as defined in and that are subject to the Apple Public Source License
* Version 2.0 (the 'License'). You may not use this file except in
* compliance with the License. The rights granted to you under the License
* may not be used to create, or enable the creation or redistribution of,
* unlawful or unlicensed copies of an Apple operating system, or to
* circumvent, violate, or enable the circumvention or violation of, any
* terms of an Apple operating system software license agreement.
*
* Please obtain a copy of the License at
* http://www.opensource.apple.com/apsl/ and read it before using this file.
*
* The Original Code and all software distributed under the License are
* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
* Please see the License for the specific language governing rights and
* limitations under the License.
*
* @APPLE_OSREFERENCE_LICENSE_HEADER_END@
*/
#include <CoreFoundation/CoreFoundation.h>
#include <unistd.h>
#include <mach/mach.h>
#include <mach/mach_time.h>
/* These externs can be removed once the prototypes make it to the SDK */
extern mach_port_name_t mk_timer_create(void);
extern kern_return_t mk_timer_arm(mach_port_name_t name, uint64_t expire_time);
#define MK_TIMER_CRITICAL (1)
extern kern_return_t mk_timer_arm_leeway(mach_port_name_t name,
uint64_t mk_timer_flags,
uint64_t mk_timer_expire_time,
uint64_t mk_timer_leeway);
struct mach_timebase_info tbinfo;
double conversion;
mach_port_t timerPort;
uint64_t interval_abs = 1000000000;
uint32_t use_leeway = 0;
uint32_t report = 1000;
uint64_t on, lastfire = 0, totaljitter = 0, max_jitter = 0, min_jitter = ~0ULL, jiterations = 0, leeway_ns = 0, leeway_abs = 0;
uint64_t deadline;
void
cfmcb(CFMachPortRef port, void *msg, CFIndex size, void *msginfo)
{
uint64_t ctime = mach_absolute_time();
uint64_t jitter = 0;
if (deadline) {
jitter = (ctime - deadline);
if (jitter > max_jitter) {
max_jitter = jitter;
}
if (jitter < min_jitter) {
min_jitter = jitter;
}
totaljitter += jitter;
if ((++jiterations % report) == 0) {
printf("max_jitter: %g (ns), min_jitter: %g (ns), average_jitter: %g (ns)\n", max_jitter * conversion, min_jitter * conversion, ((double)totaljitter / (double)jiterations) * conversion);
max_jitter = 0; min_jitter = ~0ULL; jiterations = 0; totaljitter = 0;
}
}
deadline = mach_absolute_time() + interval_abs;
if (use_leeway) {
mk_timer_arm_leeway(timerPort, MK_TIMER_CRITICAL, deadline, leeway_abs);
} else {
mk_timer_arm(timerPort, deadline);
}
}
int
main(int argc, char **argv)
{
if (argc != 4) {
printf("Usage: mktimer_test <interval_ns> <use leeway trap> <leeway_ns>\n");
return 0;
}
on = strtoul(argv[1], NULL, 0);
use_leeway = strtoul(argv[2], NULL, 0);
mach_timebase_info(&tbinfo);
conversion = ((double)tbinfo.numer / (double) tbinfo.denom);
leeway_ns = strtoul(argv[3], NULL, 0);
leeway_abs = leeway_ns / conversion;
printf("Interval in ns: %llu, timebase conversion: %g, use leeway syscall: %d, leeway_ns: %llu\n", on, conversion, !!use_leeway, leeway_ns);
interval_abs = on / conversion;
uint64_t cID = 0;
CFMachPortContext context = (CFMachPortContext){
1,
(void *)cID,
NULL,
NULL,
NULL,
};
timerPort = mk_timer_create();
CFMachPortRef port = CFMachPortCreateWithPort(NULL, timerPort, cfmcb, &context, NULL);
CFRunLoopSourceRef eventSource = CFMachPortCreateRunLoopSource(NULL, port, -1);
CFRunLoopAddSource(CFRunLoopGetCurrent(), eventSource, kCFRunLoopDefaultMode);
CFRelease(eventSource);
if (use_leeway) {
mk_timer_arm_leeway(timerPort, MK_TIMER_CRITICAL, mach_absolute_time() + interval_abs, leeway_abs);
} else {
mk_timer_arm(timerPort, mach_absolute_time() + interval_abs);
}
for (;;) {
CFRunLoopRun();
}
return 0;
}