[Differential] [Request, 19 lines] D5175: hyperv/hn: Add an option to always do transmission scheduling

[sepherosa_gmail.com (Sepherosa Ziehau)]

sepherosa_gmail.com created this revision.
sepherosa_gmail.com added reviewers: network, adrian, delphij, royger, 
decui_microsoft.com, honzhan_microsoft.com, howard0su_gmail.com.
sepherosa_gmail.com added subscribers: freebsd-net-list, 
freebsd-virtualization-list.

REVISION SUMMARY
  It is off by default.  This eases more experiment on hn(4).

REVISION DETAIL
  https://reviews.freebsd.org/D5175

AFFECTED FILES
  sys/dev/hyperv/netvsc/hv_net_vsc.h
  sys/dev/hyperv/netvsc/hv_netvsc_drv_freebsd.c

CHANGE DETAILS
  diff --git a/sys/dev/hyperv/netvsc/hv_netvsc_drv_freebsd.c 
b/sys/dev/hyperv/netvsc/hv_netvsc_drv_freebsd.c
  --- a/sys/dev/hyperv/netvsc/hv_netvsc_drv_freebsd.c
  +++ b/sys/dev/hyperv/netvsc/hv_netvsc_drv_freebsd.c
  @@ -534,6 +534,10 @@
        SYSCTL_ADD_INT(ctx, child, OID_AUTO, "direct_tx_size",
            CTLFLAG_RW, &sc->hn_direct_tx_size, 0,
            "Size of the packet for direct transmission");
  +     SYSCTL_ADD_INT(ctx, child, OID_AUTO, "sched_tx",
  +         CTLFLAG_RW, &sc->hn_sched_tx, 0,
  +         "Always schedule transmission "
  +         "instead of doing direct transmission");
   
        if (unit == 0) {
                struct sysctl_ctx_list *dc_ctx;
  @@ -1602,26 +1606,31 @@
   static void
   hn_start(struct ifnet *ifp)
   {
  -     hn_softc_t *sc;
  +     struct hn_softc *sc = ifp->if_softc;
  +
  +     if (sc->hn_sched_tx)
  +             goto do_sched;
   
  -     sc = ifp->if_softc;
        if (NV_TRYLOCK(sc)) {
                int sched;
   
                sched = hn_start_locked(ifp, sc->hn_direct_tx_size);
                NV_UNLOCK(sc);
                if (!sched)
                        return;
        }
  +do_sched:
        taskqueue_enqueue_fast(sc->hn_tx_taskq, &sc->hn_start_task);
   }
   
   static void
   hn_start_txeof(struct ifnet *ifp)
   {
  -     hn_softc_t *sc;
  +     struct hn_softc *sc = ifp->if_softc;
  +
  +     if (sc->hn_sched_tx)
  +             goto do_sched;
   
  -     sc = ifp->if_softc;
        if (NV_TRYLOCK(sc)) {
                int sched;
   
  @@ -1633,6 +1642,7 @@
                            &sc->hn_start_task);
                }
        } else {
  +do_sched:
                /*
                 * Release the OACTIVE earlier, with the hope, that
                 * others could catch up.  The task will clear the
  diff --git a/sys/dev/hyperv/netvsc/hv_net_vsc.h 
b/sys/dev/hyperv/netvsc/hv_net_vsc.h
  --- a/sys/dev/hyperv/netvsc/hv_net_vsc.h
  +++ b/sys/dev/hyperv/netvsc/hv_net_vsc.h
  @@ -1023,6 +1023,7 @@
        int             hn_txdesc_avail;
        int             hn_txeof;
   
  +     int             hn_sched_tx;
        int             hn_direct_tx_size;
        struct taskqueue *hn_tx_taskq;
        struct task     hn_start_task;

EMAIL PREFERENCES
  https://reviews.freebsd.org/settings/panel/emailpreferences/

To: sepherosa_gmail.com, network, adrian, delphij, royger, decui_microsoft.com, 
honzhan_microsoft.com, howard0su_gmail.com
Cc: freebsd-virtualization-list, freebsd-net-list

diff --git a/sys/dev/hyperv/netvsc/hv_netvsc_drv_freebsd.c b/sys/dev/hyperv/netvsc/hv_netvsc_drv_freebsd.c
--- a/sys/dev/hyperv/netvsc/hv_netvsc_drv_freebsd.c
+++ b/sys/dev/hyperv/netvsc/hv_netvsc_drv_freebsd.c
@@ -534,6 +534,10 @@
 	SYSCTL_ADD_INT(ctx, child, OID_AUTO, "direct_tx_size",
 	    CTLFLAG_RW, &sc->hn_direct_tx_size, 0,
 	    "Size of the packet for direct transmission");
+	SYSCTL_ADD_INT(ctx, child, OID_AUTO, "sched_tx",
+	    CTLFLAG_RW, &sc->hn_sched_tx, 0,
+	    "Always schedule transmission "
+	    "instead of doing direct transmission");
 
 	if (unit == 0) {
 		struct sysctl_ctx_list *dc_ctx;
@@ -1602,26 +1606,31 @@
 static void
 hn_start(struct ifnet *ifp)
 {
-	hn_softc_t *sc;
+	struct hn_softc *sc = ifp->if_softc;
+
+	if (sc->hn_sched_tx)
+		goto do_sched;
 
-	sc = ifp->if_softc;
 	if (NV_TRYLOCK(sc)) {
 		int sched;
 
 		sched = hn_start_locked(ifp, sc->hn_direct_tx_size);
 		NV_UNLOCK(sc);
 		if (!sched)
 			return;
 	}
+do_sched:
 	taskqueue_enqueue_fast(sc->hn_tx_taskq, &sc->hn_start_task);
 }
 
 static void
 hn_start_txeof(struct ifnet *ifp)
 {
-	hn_softc_t *sc;
+	struct hn_softc *sc = ifp->if_softc;
+
+	if (sc->hn_sched_tx)
+		goto do_sched;
 
-	sc = ifp->if_softc;
 	if (NV_TRYLOCK(sc)) {
 		int sched;
 
@@ -1633,6 +1642,7 @@
 			    &sc->hn_start_task);
 		}
 	} else {
+do_sched:
 		/*
 		 * Release the OACTIVE earlier, with the hope, that
 		 * others could catch up.  The task will clear the
diff --git a/sys/dev/hyperv/netvsc/hv_net_vsc.h b/sys/dev/hyperv/netvsc/hv_net_vsc.h
--- a/sys/dev/hyperv/netvsc/hv_net_vsc.h
+++ b/sys/dev/hyperv/netvsc/hv_net_vsc.h
@@ -1023,6 +1023,7 @@
 	int		hn_txdesc_avail;
 	int		hn_txeof;
 
+	int		hn_sched_tx;
 	int		hn_direct_tx_size;
 	struct taskqueue *hn_tx_taskq;
 	struct task	hn_start_task;


_______________________________________________
freebsd-virtualization@freebsd.org mailing list
https://lists.freebsd.org/mailman/listinfo/freebsd-virtualization
To unsubscribe, send any mail to 
"freebsd-virtualization-unsubscr...@freebsd.org"