vmxnet3-pending-kick.patch

From 928dc899128ac9b6d0b0cc63b20889e56f7d32ee Mon Sep 17 00:00:00 2001
From: Takuya ASADA <syuu@cloudius-systems.com>
Date: Sun, 15 Jun 2014 03:35:25 +0900
Subject: [PATCH 2/3] vmxnet3: pending kick

---
 drivers/vmxnet3.cc | 31 ++++++++++++-------------------
 drivers/vmxnet3.hh |  8 ++------
 2 files changed, 14 insertions(+), 25 deletions(-)

diff --git a/drivers/vmxnet3.cc b/drivers/vmxnet3.cc
index fda9611..7f7c035 100644
--- a/drivers/vmxnet3.cc
+++ b/drivers/vmxnet3.cc
@@ -292,7 +292,6 @@ vmxnet3::vmxnet3(pci::device &dev)
     , _mcast_list(VMXNET3_MULTICAST_MAX * VMXNET3_ETH_ALEN, VMXNET3_MULTICAST_ALIGN)
     , _receive_task([&] { receive_work(); }, sched::thread::attr().name("vmxnet3-receive"))
     , _xmit_it(this)
-    , _kick_thresh(512)
     , _xmitter(this)
     , _worker([this] { _xmitter.poll_until([] { return false; }, _xmit_it); })
 {
@@ -550,19 +549,26 @@ void vmxnet3::xmit_one_locked(void *req)
     // It was a good packet - increase the counter of a "pending for a kick"
     // packets.
     //
-    _pkts_to_kick++;
+    ++_txq[0].layout->npending;
 }
 
-void vmxnet3::kick_pending(u16 thresh)
+void vmxnet3::kick_pending()
 {
-    if (_pkts_to_kick >= thresh) {
-        _pkts_to_kick = 0;
+    kick_hw();
+}
+
+void vmxnet3::kick_pending_with_thresh()
+{
+    if (_txq[0].layout->npending >= _txq[0].layout->intr_threshold)
         kick_hw();
-    }
 }
 
 bool vmxnet3::kick_hw()
 {
+    auto &txr = _txq[0].cmd_ring;
+
+    _txq[0].layout->npending = 0;
+    _bar0->writel(VMXNET3_BAR0_TXH, txr.head);
     return true;
 }
 
@@ -591,7 +597,6 @@ int vmxnet3::txq_encap(vmxnet3_txqueue &txq, struct mbuf *m_head)
     auto txd = txr.get_desc(txr.head);
     auto sop = txr.get_desc(txr.head);
     auto gen = txr.gen ^ 1; // Owned by cpu (yet)
-    auto tx = 0;
     u64 tx_bytes = 0;
     int etype, proto, start;
 
@@ -629,7 +634,6 @@ int vmxnet3::txq_encap(vmxnet3_txqueue &txq, struct mbuf *m_head)
             txr.gen ^= 1;
         }
         gen = txr.gen;
-        tx++;
     }
     txd->layout->eop = 1;
     txd->layout->compreq = 1;
@@ -653,17 +657,6 @@ int vmxnet3::txq_encap(vmxnet3_txqueue &txq, struct mbuf *m_head)
     wmb();
     sop->layout->gen ^= 1;
 
-    if (++txq.layout->npending >= txq.layout->intr_threshold) {
-        txq.layout->npending = 0;
-        _bar0->writel(VMXNET3_BAR0_TXH, txr.head);
-    }
-    if (tx > 0) {
-        if (txq.layout->npending > 0) {
-            txq.layout->npending = 0;
-            _bar0->writel(VMXNET3_BAR0_TXH, txr.head);
-        }
-    }
-
     _txq_stats.tx_bytes += tx_bytes;
     _txq_stats.tx_packets++;
 
diff --git a/drivers/vmxnet3.hh b/drivers/vmxnet3.hh
index a0ec32a..46fe5ad 100644
--- a/drivers/vmxnet3.hh
+++ b/drivers/vmxnet3.hh
@@ -126,10 +126,8 @@ public:
     int transmit(struct mbuf* m_head);
     void receive_work();
     int xmit_prep(mbuf* m_head, void*& cooky);
-    void kick_pending(u16 thresh = 1);
-    void kick_pending_with_thresh() {
-        kick_pending(_kick_thresh);
-    }
+    void kick_pending();
+    void kick_pending_with_thresh();
     bool kick_hw();
     void wake_worker();
     int try_xmit_one_locked(void* cooky);
@@ -287,8 +285,6 @@ private:
     sched::thread _receive_task;
 
     tx_xmit_iterator<vmxnet3> _xmit_it;
-    const int _kick_thresh;
-    u16 _pkts_to_kick = 0;
     osv::xmitter<vmxnet3, 4096> _xmitter;
     sched::thread _worker;
 };
-- 
1.9.3