tadd _procwakeupandunlock to help ease locking contention on Linux 2.4. - plan9port - [fork] Plan 9 from user space
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---
DIR commit a0a331aad99bbca5a13fa4b69593061f29dc3a29
DIR parent 815552b9ed41df2f20892f6467dd47f91f93aca1
HTML Author: rsc <devnull@localhost>
Date: Thu, 6 Jan 2005 23:43:42 +0000
add _procwakeupandunlock
tto help ease locking contention
on Linux 2.4.
Diffstat:
M src/libthread/Linux.c | 27 +++++++++++++++++----------
M src/libthread/daemonize.c | 12 ++++++++++++
M src/libthread/pthread.c | 10 ++++++++++
M src/libthread/thread.c | 6 ++++--
M src/libthread/threadimpl.h | 1 +
5 files changed, 44 insertions(+), 12 deletions(-)
---
DIR diff --git a/src/libthread/Linux.c b/src/libthread/Linux.c
t@@ -32,7 +32,7 @@ _threadlock(Lock *l, int block, ulong pc)
{
int i;
static int first=1;
-if(first) {first=0; fmtinstall('T', timefmt);}
+if(first) {first=0; fmtinstall('\001', timefmt);}
USED(pc);
t@@ -48,43 +48,43 @@ if(first) {first=0; fmtinstall('T', timefmt);}
return 1;
sched_yield();
}
- /* now nice and slow */
+ /* now increasingly slow */
for(i=0; i<10; i++){
if(!_tas(&l->held))
return 1;
usleep(1);
}
-fprint(2, "%T lock loop %p from %lux\n", l, pc);
+fprint(2, "%\001 %s: lock loop1 %p from %lux\n", argv0, l, pc);
for(i=0; i<10; i++){
if(!_tas(&l->held))
return 1;
usleep(10);
}
-fprint(2, "%T lock loop %p from %lux\n", l, pc);
+fprint(2, "%\001 %s: lock loop2 %p from %lux\n", argv0, l, pc);
for(i=0; i<10; i++){
if(!_tas(&l->held))
return 1;
usleep(100);
}
-fprint(2, "%T lock loop %p from %lux\n", l, pc);
+fprint(2, "%\001 %s: lock loop3 %p from %lux\n", argv0, l, pc);
for(i=0; i<10; i++){
if(!_tas(&l->held))
return 1;
usleep(1000);
}
-fprint(2, "%T lock loop %p from %lux\n", l, pc);
+fprint(2, "%\001 %s: lock loop4 %p from %lux\n", argv0, l, pc);
for(i=0; i<10; i++){
if(!_tas(&l->held))
return 1;
usleep(10*1000);
}
-fprint(2, "%T lock loop %p from %lux\n", l, pc);
+fprint(2, "%\001 %s: lock loop5 %p from %lux\n", argv0, l, pc);
for(i=0; i<1000; i++){
if(!_tas(&l->held))
return 1;
usleep(100*1000);
}
-fprint(2, "%T lock loop %p from %lux\n", l, pc);
+fprint(2, "%\001 %s: lock loop6 %p from %lux\n", argv0, l, pc);
/* take your time */
while(_tas(&l->held))
usleep(1000*1000);
t@@ -150,13 +150,20 @@ again:
}
void
-_procwakeup(_Procrendez *r)
+_procwakeupandunlock(_Procrendez *r)
{
+ int pid;
+
+ pid = 0;
if(r->asleep){
r->asleep = 0;
assert(r->pid >= 1);
- kill(r->pid, SIGUSR1);
+ pid = r->pid;
}
+ assert(r->l);
+ unlock(r->l);
+ if(pid)
+ kill(pid, SIGUSR1);
}
/*
DIR diff --git a/src/libthread/daemonize.c b/src/libthread/daemonize.c
t@@ -1,3 +1,6 @@
+#include <u.h>
+#include <sys/time.h>
+#include <sys/resource.h>
#include "threadimpl.h"
#undef waitpid
t@@ -11,6 +14,7 @@ static void
child(void)
{
int status, pid;
+ struct rlimit rl;
notedisable("sys: child");
pid = waitpid(sigpid, &status, 0);
t@@ -21,6 +25,14 @@ child(void)
if(WIFEXITED(status))
_exit(WEXITSTATUS(status));
if(WIFSIGNALED(status)){
+ /*
+ * Make sure we don't scribble over the nice
+ * core file that our child just wrote out.
+ */
+ rl.rlim_cur = 0;
+ rl.rlim_max = 0;
+ setrlimit(RLIMIT_CORE, &rl);
+
signal(WTERMSIG(status), SIG_DFL);
raise(WTERMSIG(status));
_exit(98); /* not reached */
DIR diff --git a/src/libthread/pthread.c b/src/libthread/pthread.c
t@@ -67,6 +67,16 @@ _procwakeup(_Procrendez *r)
}
}
+void
+_procwakeupandunlock(_Procrendez *r)
+{
+ if(r->asleep){
+ r->asleep = 0;
+ pthread_cond_signal(&r->cond);
+ }
+ unlock(&r->l);
+}
+
static void
startprocfn(void *v)
{
DIR diff --git a/src/libthread/thread.c b/src/libthread/thread.c
t@@ -166,11 +166,13 @@ _threadready(_Thread *t)
p = t->proc;
lock(&p->lock);
+ p->runrend.l = &p->lock;
addthread(&p->runqueue, t);
//print("%d wake for job %d->%d\n", time(0), getpid(), p->osprocid);
if(p != proc())
- _procwakeup(&p->runrend);
- unlock(&p->lock);
+ _procwakeupandunlock(&p->runrend);
+ else
+ unlock(&p->lock);
}
int
DIR diff --git a/src/libthread/threadimpl.h b/src/libthread/threadimpl.h
t@@ -76,6 +76,7 @@ struct _Procrendez
extern void _procsleep(_Procrendez*);
extern void _procwakeup(_Procrendez*);
+extern void _procwakeupandunlock(_Procrendez*);
struct Proc
{