9vx: can finally use same sched everywhere - vx32 - Local 9vx git repository for patches.
(HTM) git clone git://r-36.net/vx32
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---
(DIR) commit 03b1418e51df3c32d0536457e0b6ed444785c040
(DIR) parent 587fe56108bafad114681688e78c8f8b189ccb77
(HTM) Author: Russ Cox <rsc@swtch.com>
Date: Thu, 3 Jul 2008 17:08:37 -0400
9vx: can finally use same sched everywhere
Diffstat:
M src/9vx/a/dat.h | 4 ----
M src/9vx/sched.c | 90 ++-----------------------------
2 files changed, 5 insertions(+), 89 deletions(-)
---
(DIR) diff --git a/src/9vx/a/dat.h b/src/9vx/a/dat.h
@@ -358,10 +358,6 @@ struct Psleep
{
int init;
pthread_mutex_t mutex;
- pthread_cond_t cond;
Pwaiter *waiter;
- int fd[2];
- vlong nread;
- vlong nwrite;
};
(DIR) diff --git a/src/9vx/sched.c b/src/9vx/sched.c
@@ -163,49 +163,7 @@ runproc(void)
/*
* Host OS process sleep and wakeup.
- * This is complicated.
- *
- * Ideally, we'd just use a single pthread_cond_t, have everyone
- * pthread_cond_wait on it, and use pthread_cond_signal
- * to wake people up. Unfortunately, that fails miserably
- * on OS X: sometimes the wakeups just plain get missed.
- * Perhaps it has something to do with all the signals that
- * are flying around.
- *
- * To work around the OS X pthreads problems, there is a
- * second implementation turned on by #defining PIPES to 1.
- * This implementation uses a pipe and reads and writes bytes
- * from the pipe to implement sleep and wakeup. Perhaps not
- * surprisingly, the naive implementation of this hangs:
- * reads miss writes. Instead, the actual implementation uses
- * select to poll whether the read would succeed, and once a
- * second it tries the read even if select doesn't think it will.
- * This timeout lets us make progress when an event gets missed
- * (happens only rarely). This is enough to get things going on
- * OS X.
- *
- * On my Athlon 64 running Linux,
- * time to run mk -a in /sys/src/9/pc:
- *
- * 90s default implementation (one pthread_cond_t)
- * 85s WAITERS (pthread_cond_t for each waiter)
- * 88s PIPES
- *
- * I implemented per-thread pthread_cond_t's to see if they
- * were any faster on non-OS X systems, but I can't see any
- * difference. Running the WAITERS version on OS X causes
- * mysterious crashes. I'm thoroughly confused.
*/
-#define PIPES 0
-#define WAITERS 1
-
-#if 0
-#undef PIPES
-#define PIPES 1
-#undef WAITERS
-#define WAITERS 0
-#endif
-
static pthread_mutex_t initmutex = PTHREAD_MUTEX_INITIALIZER;
struct Pwaiter
@@ -221,22 +179,17 @@ plock(Psleep *p)
int r;
if(!p->init){
- pthread_mutex_lock(&initmutex);
+ if((r = pthread_mutex_lock(&initmutex)) != 0)
+ panic("pthread_mutex_lock initmutex: %d", r);
if(!p->init){
p->init = 1;
pthread_mutex_init(&p->mutex, nil);
- pthread_cond_init(&p->cond, nil);
}
- pthread_mutex_unlock(&initmutex);
+ if((r = pthread_mutex_unlock(&initmutex)) != 0)
+ panic("pthread_mutex_unlock initmutex: %d", r);
}
if((r = pthread_mutex_lock(&p->mutex)) != 0)
panic("pthread_mutex_lock: %d", r);
-#if PIPES
- if(p->fd[1] == 0){
- pipe(p->fd);
- fcntl(p->fd[0], F_SETFL, fcntl(p->fd[0], F_GETFL)|O_NONBLOCK);
- }
-#endif
}
void
@@ -252,21 +205,8 @@ void
psleep(Psleep *p)
{
int r;
-
-#if PIPES
- p->nread++;
- punlock(p);
- char c;
- while(read(p->fd[0], &c, 1) < 1){
- struct pollfd pfd;
- pfd.fd = p->fd[0];
- pfd.events = POLLIN;
- pfd.revents = 0;
- poll(&pfd, 1, 1000);
- }
- plock(p);
-#elif WAITERS
Pwaiter w;
+
memset(&w, 0, sizeof w);
pthread_cond_init(&w.cond, nil);
w.next = p->waiter;
@@ -275,28 +215,12 @@ psleep(Psleep *p)
if((r = pthread_cond_wait(&w.cond, &p->mutex)) != 0)
panic("pthread_cond_wait: %d", r);
pthread_cond_destroy(&w.cond);
-#else
- if((r = pthread_cond_wait(&p->cond, &p->mutex)) != 0)
- panic("pthread_cond_wait: %d", r);
-#endif
}
void
pwakeup(Psleep *p)
{
int r;
-
-#if PIPES
- char c = 0;
- int nbad = 0;
- if(p->nwrite < p->nread){
- p->nwrite++;
- while(write(p->fd[1], &c, 1) < 1){
- if(++nbad%100 == 0)
- iprint("pwakeup: write keeps failing\n");
- }
- }
-#elif WAITERS
Pwaiter *w;
w = p->waiter;
@@ -306,9 +230,5 @@ pwakeup(Psleep *p)
if((r = pthread_cond_signal(&w->cond)) != 0)
panic("pthread_cond_signal: %d", r);
}
-#else
- if((r = pthread_cond_signal(&p->cond)) != 0)
- panic("pthread_cond_signal: %d", r);
-#endif
}