em(4): We don't embrace TIDV/TADV; nuke the related bits.

diff --git a/sys/dev/netif/em/if_em.c b/sys/dev/netif/em/if_em.c
index 400fa19..2197b69 100644 (file)
--- a/sys/dev/netif/em/if_em.c
+++ b/sys/dev/netif/em/if_em.c
@@ -315,12 +315,9 @@ static void        em_print_hw_stats(struct adapter *);
 
 static int     em_sysctl_stats(SYSCTL_HANDLER_ARGS);
 static int     em_sysctl_debug_info(SYSCTL_HANDLER_ARGS);
-static int     em_sysctl_int_delay(SYSCTL_HANDLER_ARGS);
 static int     em_sysctl_int_throttle(SYSCTL_HANDLER_ARGS);
 static int     em_sysctl_int_tx_nsegs(SYSCTL_HANDLER_ARGS);
 static void    em_add_sysctl(struct adapter *adapter);
-static void    em_add_int_delay_sysctl(struct adapter *, const char *,
-                   const char *, struct em_int_delay_info *, int, int);
 
 /* Management and WOL Support */
 static void    em_get_mgmt(struct adapter *);
@@ -352,15 +349,9 @@ DECLARE_DUMMY_MODULE(if_em);
 MODULE_DEPEND(em, ig_hal, 1, 1, 1);
 DRIVER_MODULE(if_em, pci, em_driver, em_devclass, 0, 0);
 
-/*********************************************************************
- *  Tunable default values.
- *********************************************************************/
-
-#define EM_TICKS_TO_USECS(ticks)       ((1024 * (ticks) + 500) / 1000)
-#define EM_USECS_TO_TICKS(usecs)       ((1000 * (usecs) + 512) / 1024)
-
-static int     em_tx_int_delay_dflt = EM_TICKS_TO_USECS(EM_TIDV);
-static int     em_tx_abs_int_delay_dflt = EM_TICKS_TO_USECS(EM_TADV);
+/*
+ * Tunables
+ */
 static int     em_int_throttle_ceil = EM_DEFAULT_ITR;
 static int     em_rxd = EM_DEFAULT_RXD;
 static int     em_txd = EM_DEFAULT_TXD;
@@ -371,8 +362,6 @@ static int  em_debug_sbp = FALSE;
 
 static int     em_82573_workaround = TRUE;
 
-TUNABLE_INT("hw.em.tx_int_delay", &em_tx_int_delay_dflt);
-TUNABLE_INT("hw.em.tx_abs_int_delay", &em_tx_abs_int_delay_dflt);
 TUNABLE_INT("hw.em.int_throttle_ceil", &em_int_throttle_ceil);
 TUNABLE_INT("hw.em.rxd", &em_rxd);
 TUNABLE_INT("hw.em.txd", &em_txd);
@@ -2503,11 +2492,11 @@ em_init_tx_unit(struct adapter *adapter)
        }
 
        E1000_WRITE_REG(&adapter->hw, E1000_TIPG, tipg);
-       E1000_WRITE_REG(&adapter->hw, E1000_TIDV, adapter->tx_int_delay.value);
-       if(adapter->hw.mac.type >= e1000_82540) {
-               E1000_WRITE_REG(&adapter->hw, E1000_TADV,
-                   adapter->tx_abs_int_delay.value);
-       }
+
+       /* NOTE: 0 is not allowed for TIDV */
+       E1000_WRITE_REG(&adapter->hw, E1000_TIDV, 1);
+       if(adapter->hw.mac.type >= e1000_82540)
+               E1000_WRITE_REG(&adapter->hw, E1000_TADV, 0);
 
        if (adapter->hw.mac.type == e1000_82571 ||
            adapter->hw.mac.type == e1000_82572) {
@@ -3896,64 +3885,6 @@ em_sysctl_stats(SYSCTL_HANDLER_ARGS)
        return (error);
 }
 
-static int
-em_sysctl_int_delay(SYSCTL_HANDLER_ARGS)
-{
-       struct em_int_delay_info *info;
-       struct adapter *adapter;
-       struct ifnet *ifp;
-       uint32_t regval;
-       int error, usecs, ticks;
-
-       info = (struct em_int_delay_info *)arg1;
-       usecs = info->value;
-       error = sysctl_handle_int(oidp, &usecs, 0, req);
-       if (error != 0 || req->newptr == NULL)
-               return (error);
-       if (usecs < 0 || usecs > EM_TICKS_TO_USECS(65535))
-               return (EINVAL);
-       info->value = usecs;
-       ticks = EM_USECS_TO_TICKS(usecs);
-
-       adapter = info->adapter;
-       ifp = &adapter->arpcom.ac_if;
-
-       lwkt_serialize_enter(ifp->if_serializer);
-
-       regval = E1000_READ_OFFSET(&adapter->hw, info->offset);
-       regval = (regval & ~0xffff) | (ticks & 0xffff);
-       /* Handle a few special cases. */
-       switch (info->offset) {
-       case E1000_TIDV:
-               if (ticks == 0) {
-                       /* Don't write 0 into the TIDV register. */
-                       regval++;
-               }
-               break;
-       }
-       E1000_WRITE_OFFSET(&adapter->hw, info->offset, regval);
-
-       lwkt_serialize_exit(ifp->if_serializer);
-       return (0);
-}
-
-static void
-em_add_int_delay_sysctl(struct adapter *adapter, const char *name,
-       const char *description, struct em_int_delay_info *info,
-       int offset, int value)
-{
-       info->adapter = adapter;
-       info->offset = offset;
-       info->value = value;
-
-       if (adapter->sysctl_tree != NULL) {
-               SYSCTL_ADD_PROC(&adapter->sysctl_ctx,
-                   SYSCTL_CHILDREN(adapter->sysctl_tree),
-                   OID_AUTO, name, CTLTYPE_INT|CTLFLAG_RW,
-                   info, 0, em_sysctl_int_delay, "I", description);
-       }
-}
-
 static void
 em_add_sysctl(struct adapter *adapter)
 {
@@ -4021,18 +3952,6 @@ em_add_sysctl(struct adapter *adapter)
                    em_sysctl_int_tx_nsegs, "I",
                    "# segments per TX interrupt");
        }
-
-       /* Set up some sysctls for the tunable interrupt delays */
-       em_add_int_delay_sysctl(adapter, "tx_int_delay",
-           "transmit interrupt delay in usecs", &adapter->tx_int_delay,
-           E1000_REGISTER(&adapter->hw, E1000_TIDV), em_tx_int_delay_dflt);
-       if (adapter->hw.mac.type >= e1000_82540) {
-               em_add_int_delay_sysctl(adapter, "tx_abs_int_delay",
-                   "transmit interrupt delay limit in usecs",
-                   &adapter->tx_abs_int_delay,
-                   E1000_REGISTER(&adapter->hw, E1000_TADV),
-                   em_tx_abs_int_delay_dflt);
-       }
 }
 
 static int

diff --git a/sys/dev/netif/em/if_em.h b/sys/dev/netif/em/if_em.h
index 3bf3a42..4cba7c3 100644 (file)
--- a/sys/dev/netif/em/if_em.h
+++ b/sys/dev/netif/em/if_em.h
@@ -78,6 +78,11 @@
  *   efficiency if properly tuned for specific network traffic. If the
  *   system is reporting dropped transmits, this value may be set too high
  *   causing the driver to run out of available transmit descriptors.
+ *
+ * NOTE:
+ * It is not used.  In DragonFly the TX interrupt moderation is done by
+ * conditionally setting RS bit in TX descriptors.  See the description
+ * in struct adapter.
  */
 #define EM_TIDV                                64
 
@@ -92,6 +97,11 @@
  *   packet is sent on the wire within the set amount of time.  Proper tuning,
  *   along with EM_TIDV, may improve traffic throughput in specific
  *   network conditions.
+ *
+ * NOTE:
+ * It is not used.  In DragonFly the TX interrupt moderation is done by
+ * conditionally setting RS bit in TX descriptors.  See the description
+ * in struct adapter.
  */
 #define EM_TADV                                64
 
@@ -222,14 +232,6 @@
 #define EM_FIFO_HDR                    0x10
 #define EM_82547_PKT_THRESH            0x3e0
 
-struct adapter;
-
-struct em_int_delay_info {
-       struct adapter  *adapter;       /* Back-pointer to the adapter struct */
-       int             offset;         /* Register offset to read/write */
-       int             value;          /* Current value in usecs */
-};
-
 /*
  * Bus dma allocation structure used by
  * e1000_dma_malloc and e1000_dma_free.
@@ -280,8 +282,6 @@ struct adapter {
        uint16_t                link_speed;
        uint16_t                link_duplex;
        uint32_t                smartspeed;
-       struct em_int_delay_info tx_int_delay;
-       struct em_int_delay_info tx_abs_int_delay;
        int                     int_throttle_ceil;
 
        /*