From e4dea37b8ed6ec2727d48e13bf545556ff63f882 Mon Sep 17 00:00:00 2001
From: Justine Tunney <jtunney@gmail.com>
Date: Sat, 18 Nov 2023 18:12:09 -0800
Subject: [PATCH] Make clock_nanosleep() cancel faster

---
 libc/calls/checkcancel.c     |  5 +----
 libc/calls/clock_nanosleep.c | 16 +++++++++++++---
 2 files changed, 14 insertions(+), 7 deletions(-)

diff --git a/libc/calls/checkcancel.c b/libc/calls/checkcancel.c
index ba066a0ed89..dabe9edae05 100644
--- a/libc/calls/checkcancel.c
+++ b/libc/calls/checkcancel.c
@@ -20,9 +20,8 @@
 #include "libc/intrin/atomic.h"
 #include "libc/intrin/weaken.h"
 #include "libc/thread/posixthread.internal.h"
-#ifdef __x86_64__
 
-textwindows int _check_cancel(void) {
+int _check_cancel(void) {
   if (_weaken(_pthread_cancel_ack) &&  //
       _pthread_self() && !(_pthread_self()->pt_flags & PT_NOCANCEL) &&
       atomic_load_explicit(&_pthread_self()->pt_canceled,
@@ -31,5 +30,3 @@ textwindows int _check_cancel(void) {
   }
   return 0;
 }
-
-#endif /* __x86_64__ */
diff --git a/libc/calls/clock_nanosleep.c b/libc/calls/clock_nanosleep.c
index 987d0bbdb3d..9dd7633e97d 100644
--- a/libc/calls/clock_nanosleep.c
+++ b/libc/calls/clock_nanosleep.c
@@ -18,6 +18,7 @@
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/assert.h"
 #include "libc/calls/cp.internal.h"
+#include "libc/calls/internal.h"
 #include "libc/calls/struct/timespec.h"
 #include "libc/calls/struct/timespec.internal.h"
 #include "libc/dce.h"
@@ -27,6 +28,7 @@
 #include "libc/intrin/strace.internal.h"
 #include "libc/intrin/weaken.h"
 #include "libc/runtime/clktck.h"
+#include "libc/runtime/runtime.h"
 #include "libc/sysv/consts/clock.h"
 #include "libc/sysv/consts/timer.h"
 #include "libc/sysv/errfuns.h"
@@ -108,9 +110,17 @@ static int cosmo_clock_nanosleep(int clock, int flags,
   }
 
   // spin through final scheduling quantum
-  do unassert(!clock_gettime(time_clock, &now));
-  while (timespec_cmp(now, deadline) < 0);
-  return 0;
+  int rc = 0;
+  ftrace_enabled(-1);
+  do {
+    if (_check_cancel()) {
+      rc = -1;
+      break;
+    }
+    unassert(!clock_gettime(time_clock, &now));
+  } while (timespec_cmp(now, deadline) < 0);
+  ftrace_enabled(+1);
+  return rc;
 }
 
 /**