On 01/26/2012 03:55, Luigi Rizzo wrote:
Author: luigi
Date: Thu Jan 26 09:55:16 2012
New Revision: 230572
URL: http://svn.freebsd.org/changeset/base/230572
Log:
ixgbe changes:
- remove experimental code for disabling CRC
- use the correct constant for conversion between interrupt rate
and EITR values (the previous values were off by a factor of 2)
- make dev.ix.N.queueM.interrupt_rate a RW sysctl variable.
Changing individual values affects the queue immediately,
and propagates to all interfaces at the next reinit.
- add dev.ix.N.queueM.irqs rdonly sysctl, to export the actual
interrupt counts
Netmap-related changes for ixgbe:
- use the "new" format for TX descriptors in netmap mode.
- pass interrupt mitigation delays to the user process doing poll()
on a netmap file descriptor.
On the RX side this means we will not check the ring more than once
per interrupt. This gives the process a chance to sleep and process
packets in larger batches, thus reducing CPU usage.
On the TX side we take this even further: completed transmissions are
reclaimed every half ring even if the NIC interrupts more often.
This saves even more CPU without any additional tx delays.
Generic Netmap-related changes:
- align the netmap_kring to cache lines so that there is no false sharing
(possibly useful for multiqueue NICs and MSIX interrupts, which are
handled by different cores). It's a minor improvement but it does not
cost anything.
Reviewed by: Jack Vogel
Approved by: Jack Vogel
Modified:
head/sys/dev/ixgbe/ixgbe.c
head/sys/dev/netmap/ixgbe_netmap.h
head/sys/dev/netmap/netmap.c
head/sys/dev/netmap/netmap_kern.h
*snip*
Modified: head/sys/dev/netmap/netmap_kern.h
==============================================================================
--- head/sys/dev/netmap/netmap_kern.h Thu Jan 26 09:45:14 2012
(r230571)
+++ head/sys/dev/netmap/netmap_kern.h Thu Jan 26 09:55:16 2012
(r230572)
@@ -65,13 +65,14 @@ struct netmap_kring {
struct netmap_ring *ring;
u_int nr_hwcur;
int nr_hwavail;
- u_int nr_kflags;
+ u_int nr_kflags; /* private driver flags */
+#define NKR_PENDINTR 0x1 // Pending interrupt.
u_int nkr_num_slots;
int nkr_hwofs; /* offset between NIC and netmap ring */
struct netmap_adapter *na; // debugging
struct selinfo si; /* poll/select wait queue */
-};
+} __attribute__((__aligned__(64)));
The machine-dependent param.h defines CACHE_LINE_SIZE for use in
situations like this.
Alan
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