From: Miroslav Lichvar <mlichvar@redhat.com>
Date: Wed, 10 Apr 2024 10:05:57 +0000 (+0200)
Subject: sys_linux: disable other external timestamping channels
X-Git-Tag: 4.6-pre1~24
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=a914140bd460b921ab6fd6fb29eb572f77d83a5b;p=thirdparty%2Fchrony.git

sys_linux: disable other external timestamping channels

Use new ioctls added in Linux 6.7 to disable receiving events from other
channels when enabling external timestamping on a PHC. This should save
some CPU time when other applications or chronyd instances are using
other channels of the same PHC.
---

diff --git a/sys_linux.c b/sys_linux.c
index 68496375..5fe9c0ec 100644
--- a/sys_linux.c
+++ b/sys_linux.c
@@ -990,6 +990,14 @@ SYS_Linux_SetPHCExtTimestamping(int fd, int pin, int channel,
     return 0;
   }
 
+#if defined(PTP_MASK_CLEAR_ALL) && defined(PTP_MASK_EN_SINGLE)
+  /* Disable events from other channels on this descriptor */
+  if (ioctl(fd, PTP_MASK_CLEAR_ALL))
+    DEBUG_LOG("ioctl(%s) failed : %s", "PTP_MASK_CLEAR_ALL", strerror(errno));
+  else if (ioctl(fd, PTP_MASK_EN_SINGLE, &channel))
+    DEBUG_LOG("ioctl(%s) failed : %s", "PTP_MASK_EN_SINGLE", strerror(errno));
+#endif
+
   return 1;
 }