[win-pv-devel] [PATCH 1/2] Revert "Deferring transmit completion causes MPE_Ethernet test failures"

[Paul Durrant <paul.durrant@xxxxxxxxxx>]

This reverts commit 761e6abe, but also adds a low frequency transmit
poller thread to try to avoid an unbounded transmit completion delay.

Signed-off-by: Paul Durrant <paul.durrant@xxxxxxxxxx>
---
 src/xenvif/transmitter.c | 94 +++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 93 insertions(+), 1 deletion(-)

diff --git a/src/xenvif/transmitter.c b/src/xenvif/transmitter.c
index eed0a0f..1d46f85 100644
--- a/src/xenvif/transmitter.c
+++ b/src/xenvif/transmitter.c
@@ -201,6 +201,7 @@ typedef struct _XENVIF_TRANSMITTER_RING {
     ULONG                           PacketsCompleted;
     PXENBUS_DEBUG_CALLBACK          DebugCallback;
     PXENVIF_THREAD                  WatchdogThread;
+    PXENVIF_THREAD                  CompletionThread;
 } XENVIF_TRANSMITTER_RING, *PXENVIF_TRANSMITTER_RING;
 
 struct _XENVIF_TRANSMITTER {
@@ -2769,7 +2770,6 @@ TransmitterRingPoll(
         KeMemoryBarrier();
 
         Ring->Front.rsp_cons = rsp_cons;
-        Ring->Shared->rsp_event = rsp_cons + 1;
     }
 
 done:
@@ -2796,6 +2796,8 @@ __TransmitterRingPushRequests(
 #pragma warning (push)
 #pragma warning (disable:4244)
 
+    Ring->Shared->rsp_event = Ring->Front.req_prod_pvt;
+
     // Make the requests visible to the backend
     RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&Ring->Front, Notify);
 
@@ -3251,6 +3253,79 @@ TransmitterRingWatchdog(
     return STATUS_SUCCESS;
 }
 
+#define XENVIF_TRANSMITTER_COMPLETION_PERIOD  5
+
+static NTSTATUS
+TransmitterRingCompletion(
+    IN  PXENVIF_THREAD          Self,
+    IN  PVOID                   Context
+    )
+{
+    PXENVIF_TRANSMITTER_RING    Ring = Context;
+    PROCESSOR_NUMBER            ProcNumber;
+    GROUP_AFFINITY              Affinity;
+    LARGE_INTEGER               Timeout;
+    NTSTATUS                    status;
+
+    Trace("====>\n");
+
+    if (RtlIsNtDdiVersionAvailable(NTDDI_WIN7) ) {
+        //
+        // Affinitize this thread to the same CPU as the event channel
+        // and DPC.
+        //
+        // The following functions don't work before Windows 7
+        //
+        status = KeGetProcessorNumberFromIndex(Ring->Index, &ProcNumber);
+        ASSERT(NT_SUCCESS(status));
+
+        Affinity.Group = ProcNumber.Group;
+        Affinity.Mask = (KAFFINITY)1 << ProcNumber.Number;
+        KeSetSystemGroupAffinityThread(&Affinity, NULL);
+    }
+
+    Timeout.QuadPart = 
TIME_RELATIVE(TIME_S(XENVIF_TRANSMITTER_COMPLETION_PERIOD));
+
+    for (;;) {
+        PKEVENT Event;
+        KIRQL   Irql;
+
+        Event = ThreadGetEvent(Self);
+
+        (VOID) KeWaitForSingleObject(Event,
+                                     Executive,
+                                     KernelMode,
+                                     FALSE,
+                                     &Timeout);
+        KeClearEvent(Event);
+
+        if (ThreadIsAlerted(Self))
+            break;
+
+        KeRaiseIrql(DISPATCH_LEVEL, &Irql);
+        __TransmitterRingAcquireLock(Ring);
+
+        if (Ring->Enabled) {
+            PXENVIF_TRANSMITTER Transmitter;
+            PXENVIF_FRONTEND    Frontend;
+
+            Transmitter = Ring->Transmitter;
+            Frontend = Transmitter->Frontend;
+
+            PollerTrigger(FrontendGetPoller(Frontend),
+                          Ring->Index,
+                          XENVIF_POLLER_EVENT_TRANSMIT);
+        }
+
+        __TransmitterRingReleaseLock(Ring);
+        KeLowerIrql(Irql);
+    }
+
+    Trace("<====\n");
+
+    return STATUS_SUCCESS;
+}
+
 static FORCEINLINE NTSTATUS
 __TransmitterRingInitialize(
     IN  PXENVIF_TRANSMITTER         Transmitter,
@@ -3413,8 +3488,21 @@ __TransmitterRingInitialize(
     if (!NT_SUCCESS(status))
         goto fail14;
 
+    status = ThreadCreate(TransmitterRingCompletion,
+                          *Ring,
+                          &(*Ring)->CompletionThread);
+    if (!NT_SUCCESS(status))
+        goto fail15;
+
     return STATUS_SUCCESS;
 
+fail15:
+    Error("fail15\n");
+
+    ThreadAlert((*Ring)->WatchdogThread);
+    ThreadJoin((*Ring)->WatchdogThread);
+    (*Ring)->WatchdogThread = NULL;
+
 fail14:
     Error("fail14\n");
 
@@ -3866,6 +3954,10 @@ __TransmitterRingTeardown(
     Ring->PacketsPrepared = 0;
     Ring->PacketsQueued = 0;
 
+    ThreadAlert(Ring->CompletionThread);
+    ThreadJoin(Ring->CompletionThread);
+    Ring->CompletionThread = NULL;
+
     ThreadAlert(Ring->WatchdogThread);
     ThreadJoin(Ring->WatchdogThread);
     Ring->WatchdogThread = NULL;
-- 
2.5.3


_______________________________________________
win-pv-devel mailing list
win-pv-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/cgi-bin/mailman/listinfo/win-pv-devel