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Maintain a `necessary' marker to indicate that we *probably*

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need to process a signal (usually a SIGALRM).  Check to see
if we need to process a signal both before *and* after calling
select() as older (pre-2.0) versions of ppp used to.

This handles the possibility that ppp may block at some
point (maybe due to an open() of a misconfigured device).
Previously, we'd potentially lock up in select().

The `necessary' marker reduces the increased signal checking
overhead so that at full speed with no compression transferring
an 83Mb file via a ``!ppp -direct'' device, we get a 1%
throughput gain.
This commit is contained in:
Brian Somers 1999-03-30 00:44:57 +00:00
parent 633df82af6
commit 486105bcb0
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=45126
3 changed files with 37 additions and 14 deletions
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13
usr.sbin/ppp/main.c
View File

@ -17,7 +17,7 @@
* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
* WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*
* $Id: main.c,v 1.150 1999/02/06 02:54:46 brian Exp $
* $Id: main.c,v 1.151 1999/03/07 01:02:38 brian Exp $
*
* TODO:
*/
@ -474,6 +474,17 @@ DoLoop(struct bundle *bundle)
/* Don't select - we'll be here forever */
break;
/*
* It's possible that we've had a signal since we last checked. If
* we don't check again before calling select(), we may end up stuck
* after having missed the event.... sig_Handle() tries to be as
* quick as possible if nothing is likely to have happened.
* This is only really likely if we block in open(... O_NONBLOCK)
* which will happen with a misconfigured device.
*/
if (sig_Handle())
continue;
i = select(nfds, &rfds, &wfds, &efds, NULL);
if (i < 0 && errno != EINTR) {

34
usr.sbin/ppp/sig.c
View File

@ -23,7 +23,7 @@
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $Id: sig.c,v 1.11.2.5 1998/05/01 19:25:56 brian Exp $
* $Id: sig.c,v 1.13 1998/05/21 21:48:20 brian Exp $
*/
#include <sys/types.h>
@ -34,6 +34,7 @@
#include "sig.h"
static int caused[NSIG]; /* An array of pending signals */
static int necessary; /* Anything set ? */
static sig_type handler[NSIG]; /* all start at SIG_DFL */
@ -43,6 +44,7 @@ static void
signal_recorder(int sig)
{
caused[sig - 1]++;
necessary = 1;
}
@ -77,19 +79,29 @@ sig_signal(int sig, sig_type fn)
/* Call the handlers for any pending signals */
void
int
sig_Handle()
{
int sig;
int got;
int result;
do {
got = 0;
for (sig = 0; sig < NSIG; sig++)
if (caused[sig]) {
caused[sig]--;
got++;
(*handler[sig]) (sig + 1);
}
} while (got);
result = 0;
if (necessary) {
/* We've *probably* got something in `caused' set */
necessary = 0;
/* `necessary' might go back to 1 while we're in here.... */
do {
got = 0;
for (sig = 0; sig < NSIG; sig++)
if (caused[sig]) {
caused[sig]--;
got++;
result++;
(*handler[sig])(sig + 1);
}
} while (got);
}
return result;
}

4
usr.sbin/ppp/sig.h
View File

@ -23,7 +23,7 @@
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $Id: sig.h,v 1.11.2.1 1998/05/01 19:25:57 brian Exp $
* $Id: sig.h,v 1.12 1998/05/21 21:48:23 brian Exp $
*/
typedef void (*sig_type)(int);
@ -32,4 +32,4 @@ typedef void (*sig_type)(int);
extern sig_type sig_signal(int, sig_type);
/* Call this when you want things to *actually* happen */
extern void sig_Handle(void);
extern int sig_Handle(void);