On 1.8.x-r1581305 branch, merge r1581305 and 1581315 and resolve
text conflict in svn_dep_compat.h.
git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/1.8.x-r1581305@1581326 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/subversion/include/private/svn_dep_compat.h b/subversion/include/private/svn_dep_compat.h
index 71c0b9a..693f600 100644
--- a/subversion/include/private/svn_dep_compat.h
+++ b/subversion/include/private/svn_dep_compat.h
@@ -114,6 +114,12 @@
#define SVN_LOCK_IS_BUSY(x) APR_STATUS_IS_EBUSY(x)
#endif
+#if !APR_VERSION_AT_LEAST(1,4,0)
+#ifndef apr_time_from_msec
+#define apr_time_from_msec(msec) ((apr_time_t)(msec) * 1000)
+#endif
+#endif
+
/**
* Check at compile time if the Serf version is at least a certain
* level.
diff --git a/subversion/libsvn_subr/io.c b/subversion/libsvn_subr/io.c
index f0956e2..08f2e32 100644
--- a/subversion/libsvn_subr/io.c
+++ b/subversion/libsvn_subr/io.c
@@ -1243,32 +1243,44 @@
{
/* Very simplistic but safe approach:
If the filesystem has < sec mtime we can be reasonably sure
- that the filesystem has <= millisecond precision.
+ that the filesystem has some sub-second resolution. On Windows
+ it is likely to be sub-millisecond; on Linux systems it depends
+ on the filesystem, ext4 is typically 1ms, 4ms or 10ms resolution.
## Perhaps find a better algorithm here. This will fail once
- in every 1000 cases on a millisecond precision filesystem.
+ in every 1000 cases on a millisecond precision filesystem
+ if the mtime happens to be an exact second.
But better to fail once in every thousand cases than every
time, like we did before.
- (All tested filesystems I know have at least microsecond precision.)
Note for further research on algorithm:
- FAT32 has < 1 sec precision on ctime, but 2 sec on mtime */
+ FAT32 has < 1 sec precision on ctime, but 2 sec on mtime.
- /* Sleep for at least 1 millisecond.
- (t < 1000 will be round to 0 in apr) */
- apr_sleep(1000);
+ Linux/ext4 with CONFIG_HZ=250 has high resolution
+ apr_time_now and although the filesystem timestamps
+ have similar high precision they are only updated with
+ a coarser 4ms resolution. */
- return;
+ /* 10 milliseconds after now. */
+#ifndef SVN_HI_RES_SLEEP_MS
+#define SVN_HI_RES_SLEEP_MS 10
+#endif
+ then = now + apr_time_from_msec(SVN_HI_RES_SLEEP_MS);
}
- now = apr_time_now(); /* Extract the time used for the path stat */
-
- if (now >= then)
- return; /* Passing negative values may suspend indefinitely (Windows) */
+ /* Remove time taken to do stat() from sleep. */
+ now = apr_time_now();
}
- apr_sleep(then - now);
+ if (now >= then)
+ return; /* Passing negative values may suspend indefinitely (Windows) */
+
+ /* (t < 1000 will be round to 0 in apr) */
+ if (then - now < 1000)
+ apr_sleep(1000);
+ else
+ apr_sleep(then - now);
}
