jehanne/qa/lib/c/wlockt0.c

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/*
* This file is part of Jehanne.
*
* Copyright (C) 2015 Giacomo Tesio <giacomo@tesio.it>
*
* Jehanne is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, version 2 of the License.
*
* Jehanne is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with Jehanne. If not, see <http://www.gnu.org/licenses/>.
*/
#include <u.h>
#include <libc.h>
/* verify that wlockt returns 0 on timeout */
#define NPROC 50
RWLock alwaysLocked; /* held by main process, writers will timeout */
int killerProc; /* pid, will kill the other processes if starved */
int elapsed[NPROC];
int32_t completed;
QLock rl;
Rendez rStart;
Rendez rCompleted;
int verbose = 0;
void
killKiller(void)
{
postnote(PNPROC, killerProc, "interrupt");
}
void
stopAllAfter(int seconds)
{
int pid;
switch((pid = rfork(RFMEM|RFPROC|RFNOWAIT)))
{
case 0:
if(verbose)
print("killer proc started: pid %d\n", getpid());
sleep(seconds * 1000);
postnote(PNGROUP, killerProc, "timedout");
if(verbose)
print("killer proc timedout: pid %d\n", getpid());
exits("FAIL");
case -1:
fprint(2, "stopAllAfter: %r\n");
exits("rfork fails");
default:
if(verbose)
print("killer proc spawn: pid %d\n", getpid());
killerProc = pid;
atexit(killKiller);
}
}
int
handletimeout(void *v, char *s)
{
if(strcmp(s, "timedout") == 0){
if(verbose)
print("%d: noted: %s\n", getpid(), s);
print("FAIL: timedout\n");
exits("FAIL");
}
return 0;
}
int
handlefail(void *v, char *s)
{
if(strncmp(s, "fail", 4) == 0){
if(verbose)
print("%d: noted: %s\n", getpid(), s);
print("FAIL: %s\n", s);
exits("FAIL");
}
return 0;
}
char *
waiter(int index)
{
int64_t start, end;
/* wait for the alwaysLocked to be locked by the main process */
qlock(&rl);
while(alwaysLocked._readers == 0)
rsleep(&rStart);
qunlock(&rl);
/* try to lock for ~1000 ms */
start = nsec();
end = start;
if(verbose)
print("writer %d: started\n", getpid());
if(wlockt(&alwaysLocked, 1000)){
if(verbose)
print("writer %d failed: got the wlock\n", getpid());
wunlock(&alwaysLocked);
postnote(PNGROUP, getpid(), smprint("fail: writer %d got the wlock", getpid()));
} else {
end = nsec();
if(verbose)
print("writer %d: wlockt timedout in %lld ms\n", getpid(), (end - start) / (1000*1000));
}
/* notify the main process that we have completed */
qlock(&rl);
elapsed[index] = end - start;
++completed;
rwakeup(&rCompleted);
qunlock(&rl);
return end != start ? nil : "FAIL";
}
void
spawnWaiter(int index)
{
int pid;
char * res;
switch((pid = rfork(RFMEM|RFPROC|RFNOWAIT)))
{
case 0:
res = waiter(index);
exits(res);
break;
case -1:
print("spawnWaiter: %r\n");
exits("rfork fails");
break;
default:
if(verbose)
print("spawn writer %d\n", pid);
break;
}
}
void
main(void)
{
int i;
int64_t average;
rfork(RFNOTEG|RFREND);
rStart.l = &rl;
rCompleted.l = &rl;
if(verbose)
print("main: started with pid %d\n", getpid());
for(i = 0; i < NPROC; ++i){
spawnWaiter(i);
}
stopAllAfter(30);
if (!atnotify(handletimeout, 1)){
fprint(2, "atnotify(handletimeout): %r\n");
exits("atnotify fails");
}
if (!atnotify(handlefail, 1)){
fprint(2, "atnotify(handlefail): %r\n");
exits("atnotify fails");
}
if(verbose)
print("main: ready to lock...\n");
qlock(&rl);
rlock(&alwaysLocked);
if(verbose)
print("main: got the alwaysLocked: wakeup all writers...\n");
rwakeupall(&rStart);
if(verbose)
print("main: got the alwaysLocked: wakeup all writers... done\n");
qunlock(&rl);
qlock(&rl);
if(verbose)
print("main: waiting all writers to timeout...\n");
while(completed < NPROC){
rsleep(&rCompleted);
if(verbose && completed < NPROC)
print("main: awaked, but %d writers are still pending\n", NPROC - completed);
}
runlock(&alwaysLocked);
qunlock(&rl);
if(verbose)
print("main: waiting all writers to timeout... done\n");
average = 0;
for(i = 0; i < NPROC; ++i){
average += elapsed[i];
}
average = average / NPROC / (1000 * 1000);
if(average > 900 && average < 1300) /* 30% error on timeout is acceptable */
{
print("PASS\n");
exits("PASS");
}
print("FAIL: average timeout too long %lld ms\n", average);
exits("FAIL");
}