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authorRich Felker <dalias@aerifal.cx>2011-03-10 18:31:37 -0500
committerRich Felker <dalias@aerifal.cx>2011-03-10 18:31:37 -0500
commit5fcebcde6aeba6ae4a339790beba5331fbcd3b6e (patch)
tree8ed33494f1f8ac060f756027847b73d897274d7a
parentdc54a7cbb9f0aad6f614131ecc683fbb0b717115 (diff)
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optimize pthread termination in the non-detached case
we can avoid blocking signals by simply using a flag to mark that the thread has exited and prevent it from getting counted in the rsyscall signal-pingpong. this restores the original pthread create/join throughput from before the sigprocmask call was added.
-rw-r--r--src/internal/pthread_impl.h1
-rw-r--r--src/thread/pthread_create.c19
2 files changed, 16 insertions, 4 deletions
diff --git a/src/internal/pthread_impl.h b/src/internal/pthread_impl.h
index adb80f2f..c1740111 100644
--- a/src/internal/pthread_impl.h
+++ b/src/internal/pthread_impl.h
@@ -36,6 +36,7 @@ struct pthread {
struct __ptcb *cancelbuf;
void **tsd;
pthread_attr_t attr;
+ volatile int dead;
};
#define __SU (sizeof(size_t)/sizeof(int))
diff --git a/src/thread/pthread_create.c b/src/thread/pthread_create.c
index 9c24b844..d829fa26 100644
--- a/src/thread/pthread_create.c
+++ b/src/thread/pthread_create.c
@@ -25,13 +25,16 @@ void __pthread_unwind_next(struct __ptcb *cb)
}
}
- syscall4(__NR_rt_sigprocmask, SIG_BLOCK, (long)(uint64_t[1]){-1},0,8);
+ /* Mark this thread dead before decrementing count */
+ self->dead = 1;
if (!a_fetch_add(&libc.threads_minus_1, -1))
exit(0);
- if (self->detached && self->map_base)
+ if (self->detached && self->map_base) {
+ syscall4(__NR_rt_sigprocmask, SIG_BLOCK, (long)(uint64_t[1]){-1},0,8);
__unmapself(self->map_base, self->map_size);
+ }
__syscall_exit(0);
}
@@ -76,9 +79,17 @@ static struct {
static void rsyscall_handler(int sig, siginfo_t *si, void *ctx)
{
- if (si->si_code > 0 || si->si_pid != __pthread_self()->pid) return;
+ struct pthread *self = __pthread_self();
+
+ if (si->si_code > 0 || si->si_pid != self->pid ||
+ rs.cnt == libc.threads_minus_1) return;
- if (rs.cnt == libc.threads_minus_1) return;
+ /* Threads which have already decremented themselves from the
+ * thread count must not increment rs.cnt or otherwise act. */
+ if (self->dead) {
+ __wait(&rs.hold, 0, 1, 1);
+ return;
+ }
if (syscall6(rs.nr, rs.arg[0], rs.arg[1], rs.arg[2],
rs.arg[3], rs.arg[4], rs.arg[5]) < 0 && !rs.err) rs.err=errno;