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MFcalloutng:

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kern_nanosleep() is now converted to use tsleep_sbt(). With this change
nanosleep() and usleep() can handle sub-tick precision for timeouts.
Also, try to help coalesce of events passing as argument to tsleep_bt()
a precision value calculated as a percentage of the sleep time.
This percentage is default 5%, but it can tuned according to users
need via the sysctl interface.

Sponsored by:	Google Summer of Code 2012, iXsystems inc.
Tested by:	flo, marius, ian, markj, Fabian Keil
This commit is contained in:
Davide Italiano 2013-03-04 15:57:41 +00:00
parent 037637812d
commit 098176f0d0
1 changed files with 23 additions and 23 deletions
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46
sys/kern/kern_time.c
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@ -43,6 +43,7 @@ __FBSDID("$FreeBSD$");
#include <sys/resourcevar.h>
#include <sys/signalvar.h>
#include <sys/kernel.h>
#include <sys/sleepqueue.h>
#include <sys/syscallsubr.h>
#include <sys/sysctl.h>
#include <sys/sysent.h>
@ -481,38 +482,37 @@ static int nanowait;
int
kern_nanosleep(struct thread *td, struct timespec *rqt, struct timespec *rmt)
{
struct timespec ts, ts2, ts3;
struct timeval tv;
struct timespec ts;
sbintime_t sbt, sbtt, prec, tmp;
int error;
if (rqt->tv_nsec < 0 || rqt->tv_nsec >= 1000000000)
return (EINVAL);
if (rqt->tv_sec < 0 || (rqt->tv_sec == 0 && rqt->tv_nsec == 0))
return (0);
getnanouptime(&ts);
timespecadd(&ts, rqt);
TIMESPEC_TO_TIMEVAL(&tv, rqt);
for (;;) {
error = tsleep(&nanowait, PWAIT | PCATCH, "nanslp",
tvtohz(&tv));
getnanouptime(&ts2);
if (error != EWOULDBLOCK) {
if (error == ERESTART)
error = EINTR;
if (rmt != NULL) {
timespecsub(&ts, &ts2);
if (ts.tv_sec < 0)
timespecclear(&ts);
*rmt = ts;
}
return (error);
tmp = tstosbt(*rqt);
prec = tmp;
prec >>= tc_precexp;
if (TIMESEL(&sbt, tmp))
sbt += tc_tick_sbt;
sbt += tmp;
error = tsleep_sbt(&nanowait, PWAIT | PCATCH, "nanslp", sbt, prec,
C_ABSOLUTE);
if (error != EWOULDBLOCK) {
if (error == ERESTART)
error = EINTR;
TIMESEL(&sbtt, tmp);
if (rmt != NULL) {
ts = sbttots(sbt - sbtt);
if (ts.tv_sec < 0)
timespecclear(&ts);
*rmt = ts;
}
if (timespeccmp(&ts2, &ts, >=))
if (sbtt >= sbt)
return (0);
ts3 = ts;
timespecsub(&ts3, &ts2);
TIMESPEC_TO_TIMEVAL(&tv, &ts3);
return (error);
}
return (0);
}
#ifndef _SYS_SYSPROTO_H_