Author: jmallett
Date: Sun Jan 9 23:46:24 2011
New Revision: 217212
URL: http://svn.freebsd.org/changeset/base/217212
Log:
Now that we correctly enable rx interrupts on all cores, performance has
gotten
quite awful, because e.g. 4 packets will come in and get processed on 4
different cores at the same time, really battling with the TCP stack quite
painfully. For now, just run one task at a time.
This gets performance up in most cases to where it was before the correctness
fixes that got interrupts to run on all cores (except in high-load TCP
transmit
cases where all we're handling receive for is ACKs) and in some cases it's
better now. What would be ideal would be to use a more advanced interrupt
mitigation strategy and possibly to use different workqueue groups per port
for
multi-port systems, and so on, but this is a fine stopgap.
Modified:
head/sys/mips/cavium/octe/ethernet-rx.c
Modified: head/sys/mips/cavium/octe/ethernet-rx.c
==============================================================================
--- head/sys/mips/cavium/octe/ethernet-rx.c Sun Jan 9 23:20:01 2011
(r217211)
+++ head/sys/mips/cavium/octe/ethernet-rx.c Sun Jan 9 23:46:24 2011
(r217212)
@@ -54,6 +54,8 @@ extern struct ifnet *cvm_oct_device[];
static struct task cvm_oct_task;
static struct taskqueue *cvm_oct_taskq;
+static int cvm_oct_rx_active;
+
/**
* Interrupt handler. The interrupt occurs whenever the POW
* transitions from 0->1 packets in our group.
@@ -70,7 +72,13 @@ int cvm_oct_do_interrupt(void *dev_id)
cvmx_write_csr(CVMX_POW_WQ_INT, 1<<pow_receive_group);
else
cvmx_write_csr(CVMX_POW_WQ_INT, 0x10001<<pow_receive_group);
- taskqueue_enqueue(cvm_oct_taskq, &cvm_oct_task);
+
+ /*
+ * Schedule task if there isn't one running.
+ */
+ if (atomic_cmpset_int(&cvm_oct_rx_active, 0, 1))
+ taskqueue_enqueue(cvm_oct_taskq, &cvm_oct_task);
+
return FILTER_HANDLED;
}
@@ -353,6 +361,19 @@ void cvm_oct_tasklet_rx(void *context, i
cvm_oct_free_work(work);
}
+ /*
+ * If we hit our limit, schedule another task while we clean up.
+ */
+ if (INTERRUPT_LIMIT != 0 && rx_count == MAX_RX_PACKETS) {
+ taskqueue_enqueue(cvm_oct_taskq, &cvm_oct_task);
+ } else {
+ /*
+ * No more packets, all done.
+ */
+ if (!atomic_cmpset_int(&cvm_oct_rx_active, 1, 0))
+ panic("%s: inconsistent rx active state.", __func__);
+ }
+
/* Restore the original POW group mask */
cvmx_write_csr(CVMX_POW_PP_GRP_MSKX(coreid), old_group_mask);
if (USE_ASYNC_IOBDMA) {
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