ipmiwatchdog: Limit the number of resets

We send resets after the completion of every istep and in the middle of
some of our known long isteps. In some instances during boot, during
fast isteps or custom routines, we can send 10 or more resets within the
same second. This generates a lot of IPMI traffic and causes the BMC to
spend more time processing resets than is needed. Since our timeout is
relatively long (120s right now), it should be no issue to limit the
number of resets to one reset every 1-2 seconds

I've tested this on a zaius machine and it reduced load on the BMC and
made clean boots a little faster.

Resolves #140

Signed-off-by: William A. Kennington III <wak@google.com>
Change-Id: I60d26af082e1ddb29624fc22a0513b47526978d5
Reviewed-on: http://ralgit01.raleigh.ibm.com/gerrit1/59291
Tested-by: Jenkins Server <pfd-jenkins+hostboot@us.ibm.com>
Tested-by: FSP CI Jenkins <fsp-CI-jenkins+hostboot@us.ibm.com>
Reviewed-by: Daniel M. Crowell <dcrowell@us.ibm.com>
Tested-by: Jenkins OP Build CI <op-jenkins+hostboot@us.ibm.com>
Tested-by: Jenkins OP HW <op-hw-jenkins+hostboot@us.ibm.com>
Reviewed-by: William G. Hoffa <wghoffa@us.ibm.com>

1 files changed, 14 insertions, 0 deletions

diff --git a/src/usr/ipmi/ipmiwatchdog.C b/src/usr/ipmi/ipmiwatchdog.C
index 3efdbfbb7..2f9f28f74 100644
--- a/src/usr/ipmi/ipmiwatchdog.C
+++ b/src/usr/ipmi/ipmiwatchdog.C
@@ -6,6 +6,7 @@
 /* OpenPOWER HostBoot Project                                             */
 /*                                                                        */
 /* Contributors Listed Below - COPYRIGHT 2014,2018                        */
+/* [+] Google Inc.                                                        */
 /* [+] International Business Machines Corp.                              */
 /*                                                                        */
 /*                                                                        */
@@ -39,6 +40,7 @@
 #include <ipmi/ipmiwatchdog.H>
 #include <ipmi/ipmiif.H>
 #include <sys/time.h>
+#include <time.h>
 
 /******************************************************************************/
 // Globals/Constants
@@ -104,6 +106,18 @@ errlHndl_t resetWatchDogTimer()
 {
     errlHndl_t err_ipmi = NULL;
 
+    // Limit the amount of sent watchdog resets to once per second to make
+    // sure that we don't overload the BMC with resets during quickly
+    // completing ISTEPs. For simplicity we only compare the tv_sec so
+    // the grace period may be almost 2 seconds.
+    static uint64_t last_reset_sec;
+    timespec_t now;
+    clock_gettime(CLOCK_MONOTONIC, &now);
+    if (last_reset_sec + 1 >= now.tv_sec)
+    {
+        return NULL;
+    }
+    last_reset_sec = now.tv_sec;
 
     // reset command does not take any request data
     size_t len = 0;