On 07/11/2012 01:30 AM, richard -rw- weinberger wrote:
> On Tue, Jul 10, 2012 at 2:45 PM, Toralf Förster <toralf.foers...@gmx.de>
> wrote:
>> I tested the script of John Stultz (https://lkml.org/lkml/2012/7/1/203)
>> at a UML of an unstable Gentoo Linux with recent host
>> kernel linux-v3.5-rc5-98-g9e85a6f
>> (without his proposed patches) and observed the following time jump of
>> roughly 2 1/2 hours :
>
> I don't know what John's programing is exactly doing.
> What is the expected result?
>
I wouldn't expeczt more than 1 seconds time shift from the program
(attached for convenience)
--
MfG/Sincerely
Toralf Förster
pgp finger print: 7B1A 07F4 EC82 0F90 D4C2 8936 872A E508 7DB6 9DA3
/* Leap second test
* by: john stultz (johns...@us.ibm.com)
* (C) Copyright IBM 2012
* Licensed under the GPL
*/
#include <stdio.h>
#include <time.h>
#include <sys/time.h>
#include <sys/timex.h>
#define CALLS_PER_LOOP 64
#define NSEC_PER_SEC 1000000000ULL
/* returns 1 if a <= b, 0 otherwise */
static inline int in_order(struct timespec a, struct timespec b)
{
if(a.tv_sec < b.tv_sec)
return 1;
if(a.tv_sec > b.tv_sec)
return 0;
if(a.tv_nsec > b.tv_nsec)
return 0;
return 1;
}
int main(void)
{
struct timeval tv;
struct timex tx;
struct timespec list[CALLS_PER_LOOP];
int i, inconsistent;
int clock_type = CLOCK_REALTIME;
long now, then;
/* Get the current time */
gettimeofday(&tv, NULL);
/* Calculate the next leap second */
tv.tv_sec += 86400 - tv.tv_sec % 86400;
/* Set the time to be 10 seconds from that time */
tv.tv_sec -= 10;
settimeofday(&tv, NULL);
/* Set the leap second insert flag */
tx.modes = ADJ_STATUS;
tx.status = STA_INS;
adjtimex(&tx);
clock_gettime(clock_type, &list[0]);
now = then = list[0].tv_sec;
while(now - then < 30){
inconsistent = 0;
/* Fill list */
for(i=0; i < CALLS_PER_LOOP; i++)
clock_gettime(clock_type, &list[i]);
/* Check for inconsistencies */
for(i=0; i < CALLS_PER_LOOP-1; i++)
if(!in_order(list[i],list[i+1]))
inconsistent = i;
/* display inconsistency */
if(inconsistent){
unsigned long long delta;
for(i=0; i < CALLS_PER_LOOP; i++){
if(i == inconsistent)
printf("--------------------\n");
printf("%lu:%lu\n",list[i].tv_sec,
list[i].tv_nsec);
if(i == inconsistent + 1 )
printf("--------------------\n");
}
delta = list[inconsistent].tv_sec*NSEC_PER_SEC;
delta += list[inconsistent].tv_nsec;
delta -= list[inconsistent+1].tv_sec*NSEC_PER_SEC;
delta -= list[inconsistent+1].tv_nsec;
printf("Delta: %llu ns\n", delta);
fflush(0);
break;
}
now = list[0].tv_sec;
}
/* clear TIME_WAIT */
tx.modes = ADJ_STATUS;
tx.status = 0;
adjtimex(&tx);
return 0;
}
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