helper_thread: Increase timer accuracy

The helper_thread uses select() to wait for the next event. select() rounds
up its timeout argument to 1 / HZ. Increase timer accuracy by using a
high-res timer if possible. This patch has been tested by running the
following fio command and by verifying that the next_log and
msec_to_next_event were always above 100 ms:

./fio --debug=helperthread --bandwidth-log --write_bw_log=log --log_avg_msec=1000 --ioengine=null --name=null --size=1G --rw=randwrite --loops=999999 --runtime=60

Signed-off-by: Bart Van Assche <bvanassche@acm.org>

1 files changed, 21 insertions, 0 deletions

diff --git a/configure b/configure
index 3846881c..39a9248d 100755
--- a/configure
+++ b/configure
@@ -2682,6 +2682,24 @@ else
   pdb=no
 fi
 print_config "Windows PDB generation" "$pdb"
+
+##########################################
+# check for timerfd support
+timerfd_create="no"
+cat > $TMPC << EOF
+#include <sys/time.h>
+#include <sys/timerfd.h>
+
+int main(int argc, char **argv)
+{
+	return timerfd_create(CLOCK_MONOTONIC, TFD_NONBLOCK);
+}
+EOF
+if compile_prog "" "" "timerfd_create"; then
+  timerfd_create="yes"
+fi
+print_config "timerfd_create" "$timerfd_create"
+
 #############################################################################
 
 if test "$wordsize" = "64" ; then
@@ -2983,6 +3001,9 @@ fi
 if test "$statx_syscall" = "yes"; then
   output_sym "CONFIG_HAVE_STATX_SYSCALL"
 fi
+if test "$timerfd_create" = "yes"; then
+  output_sym "CONFIG_HAVE_TIMERFD_CREATE"
+fi
 if test "$fallthrough" = "yes"; then
   CFLAGS="$CFLAGS -Wimplicit-fallthrough"
 fi