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https://github.com/genodelabs/genode.git
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31e8b50b7c
A bunch of transmit requests received by the Uplink server (nic_router) are currently added one by one to the ring buffer and every time the hardware is notified to process each single request. Instead, add as many as possible transmit requests in the ring buffer of the hardware and when done trigger the hardware to process the ring. Additionally, don't receive an "processed" TX IRQ for each element in the ring, which causes high CPU load. With this commit the TX IRQs in the ipxe driver for a iperf -c X.X.X.X -t 60 from within a VM to the outside iperf server is reduced from about ~2'600'000 IRQs to about ~200'000. The overall CPU load for the driver (when executed alone on CPU 0) is reduced from ~85 percent load to ~45 percent load. Issue #5149
112 lines
2.9 KiB
Diff
112 lines
2.9 KiB
Diff
--- a/src/drivers/net/intel.c
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+++ b/src/drivers/net/intel.c
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@@ -717,6 +717,23 @@
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intel_reset ( intel );
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}
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+static int intel_transmit_done ( struct net_device *netdev)
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+{
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+ struct intel_nic *intel = netdev->priv;
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+
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+ unsigned int tx_tail;
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+
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+ tx_tail = ( intel->tx.prod % INTEL_NUM_TX_DESC );
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+
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+ wmb();
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+
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+ /* Notify card that there are packets ready to transmit */
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+ writel ( tx_tail, intel->regs + intel->tx.reg + INTEL_xDT );
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+
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+ return 0;
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+
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+}
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+
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/**
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* Transmit packet
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*
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@@ -745,10 +762,11 @@
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address = virt_to_bus ( iobuf->data );
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len = iob_len ( iobuf );
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intel->tx.describe ( tx, address, len );
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- wmb();
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- /* Notify card that there are packets ready to transmit */
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- writel ( tx_tail, intel->regs + intel->tx.reg + INTEL_xDT );
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+ /* ptr check just in case we make transmit_done configurable - set/unset */
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+ if ((intel->tx.cons == ((tx_tail + 1) % INTEL_NUM_TX_DESC)) || !netdev->op->transmit_done) {
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+ intel_transmit_done(netdev);
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+ }
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DBGC2 ( intel, "INTEL %p TX %d is [%llx,%llx)\n", intel, tx_idx,
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( ( unsigned long long ) address ),
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@@ -845,7 +863,7 @@
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return;
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/* Poll for TX completions, if applicable */
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- if ( icr & INTEL_IRQ_TXDW )
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+ if ( icr & (INTEL_IRQ_TXDW | INTEL_IRQ_TXQE))
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intel_poll_tx ( netdev );
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/* Poll for RX completions, if applicable */
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@@ -882,7 +900,7 @@
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struct intel_nic *intel = netdev->priv;
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uint32_t mask;
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- mask = ( INTEL_IRQ_TXDW | INTEL_IRQ_LSC | INTEL_IRQ_RXT0 );
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+ mask = ( INTEL_IRQ_TXQE | INTEL_IRQ_LSC | INTEL_IRQ_RXT0 );
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if ( enable ) {
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writel ( mask, intel->regs + INTEL_IMS );
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} else {
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@@ -897,6 +915,7 @@
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.transmit = intel_transmit,
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.poll = intel_poll,
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.irq = intel_irq,
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+ .transmit_done = intel_transmit_done,
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};
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/******************************************************************************
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--- a/src/include/ipxe/netdevice.h
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+++ b/src/include/ipxe/netdevice.h
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@@ -260,6 +260,8 @@
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* supported.
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*/
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void ( * irq ) ( struct net_device *netdev, int enable );
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+
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+ int ( * transmit_done ) ( struct net_device *netdev);
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};
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/** Network device error */
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@@ -575,6 +577,7 @@
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extern void netdev_link_err ( struct net_device *netdev, int rc );
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extern void netdev_link_down ( struct net_device *netdev );
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extern int netdev_tx ( struct net_device *netdev, struct io_buffer *iobuf );
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+extern int netdev_tx_done ( struct net_device *netdev );
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extern void netdev_tx_defer ( struct net_device *netdev,
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struct io_buffer *iobuf );
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extern void netdev_tx_err ( struct net_device *netdev,
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--- a/src/net/netdevice.c
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+++ b/src/net/netdevice.c
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@@ -213,6 +213,22 @@
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return rc;
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}
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+int netdev_tx_done ( struct net_device *netdev ) {
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+
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+ int rc;
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+
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+ /* Avoid calling transmit() on unopened network devices */
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+ if ( ! netdev_is_open ( netdev ) ) {
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+ rc = -ENETUNREACH;
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+ return rc;
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+ }
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+
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+ if ( !netdev->op || !netdev->op->transmit_done )
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+ return -ENETUNREACH;
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+
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+ return netdev->op->transmit_done ( netdev );
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+}
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+
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/**
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* Defer transmitted packet
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*
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