Author: davide
Date: Mon Mar 4 15:57:41 2013
New Revision: 247797
URL: http://svnweb.freebsd.org/changeset/base/247797
Log:
MFcalloutng:
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
Modified:
head/sys/kern/kern_time.c
Modified: head/sys/kern/kern_time.c
==============================================================================
--- head/sys/kern/kern_time.c Mon Mar 4 15:34:59 2013 (r247796)
+++ head/sys/kern/kern_time.c Mon Mar 4 15:57:41 2013 (r247797)
@@ -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_
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