[src/trunk]: src/sys/dev/pci adjust the condition for reusing checksum contex...

[jdolecek <jdolecek%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/a085594ea109
branches:  trunk
changeset: 1009008:a085594ea109
user:      jdolecek <jdolecek%NetBSD.org@localhost>
date:      Thu Apr 09 06:55:51 2020 +0000

description:
adjust the condition for reusing checksum context, wm_tx_offload() can
be used even for multiqueue case

enable only when the chip supports exactly one queue (same as FreeBSD) -
anything multiqueue-capable later than 82574 should work, but I don't
have the hw to test

diffstat:

 sys/dev/pci/if_wm.c |  62 ++++++++++++++++++++++++++++------------------------
 1 files changed, 33 insertions(+), 29 deletions(-)

diffs (83 lines):

diff -r 92fc760e5e9f -r a085594ea109 sys/dev/pci/if_wm.c
--- a/sys/dev/pci/if_wm.c       Thu Apr 09 06:49:37 2020 +0000
+++ b/sys/dev/pci/if_wm.c       Thu Apr 09 06:55:51 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: if_wm.c,v 1.673 2020/04/08 21:57:24 jdolecek Exp $     */
+/*     $NetBSD: if_wm.c,v 1.674 2020/04/09 06:55:51 jdolecek Exp $     */
 
 /*
  * Copyright (c) 2001, 2002, 2003, 2004 Wasabi Systems, Inc.
@@ -82,7 +82,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: if_wm.c,v 1.673 2020/04/08 21:57:24 jdolecek Exp $");
+__KERNEL_RCSID(0, "$NetBSD: if_wm.c,v 1.674 2020/04/09 06:55:51 jdolecek Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_net_mpsafe.h"
@@ -7558,33 +7558,37 @@
         * contexts on this hardware platform and must generate a new
         * context every time.  82574L hardware spec, section 7.2.6,
         * second note.
-        *
-        * Setting up new checksum offload context for every
-        * frames takes a lot of processing time for hardware.
-        * This also reduces performance a lot for small sized
-        * frames so avoid it if driver can use previously
-        * configured checksum offload context.
-        * For TSO, in theory we can use the same TSO context if and only if
-        * frame is the same type(IP/TCP) and the same MSS. However
-        * checking whether a frame has the same IP/TCP structure is
-        * hard thing so just ignore that and always restablish a
-        * new TSO context.
-        */
-       KASSERT(!wm_is_using_multiqueue(sc));
-       if ((m0->m_pkthdr.csum_flags & (M_CSUM_TSOv4 | M_CSUM_TSOv6)) == 0) {
-               if (txq->txq_last_hw_cmd == cmd &&
-                   txq->txq_last_hw_fields == fields &&
-                   txq->txq_last_hw_ipcs == (ipcs & 0xffff) &&
-                   txq->txq_last_hw_tucs == (tucs & 0xffff)) {
-                       WM_Q_EVCNT_INCR(txq, skipcontext);
-                       return;
-               }
-       }
-
-       txq->txq_last_hw_cmd = cmd;
-       txq->txq_last_hw_fields = fields;
-       txq->txq_last_hw_ipcs = (ipcs & 0xffff);
-       txq->txq_last_hw_tucs = (tucs & 0xffff);
+        */
+       if (sc->sc_nqueues < 2) {
+               /*
+                *
+                * Setting up new checksum offload context for every
+                * frames takes a lot of processing time for hardware.
+                * This also reduces performance a lot for small sized
+                * frames so avoid it if driver can use previously
+                * configured checksum offload context.
+                * For TSO, in theory we can use the same TSO context only if
+                * frame is the same type(IP/TCP) and the same MSS. However
+                * checking whether a frame has the same IP/TCP structure is
+                * hard thing so just ignore that and always restablish a
+                * new TSO context.
+                */
+               if ((m0->m_pkthdr.csum_flags & (M_CSUM_TSOv4 | M_CSUM_TSOv6))
+                   == 0) {
+                       if (txq->txq_last_hw_cmd == cmd &&
+                           txq->txq_last_hw_fields == fields &&
+                           txq->txq_last_hw_ipcs == (ipcs & 0xffff) &&
+                           txq->txq_last_hw_tucs == (tucs & 0xffff)) {
+                               WM_Q_EVCNT_INCR(txq, skipcontext);
+                               return;
+                       }
+               }
+
+               txq->txq_last_hw_cmd = cmd;
+               txq->txq_last_hw_fields = fields;
+               txq->txq_last_hw_ipcs = (ipcs & 0xffff);
+               txq->txq_last_hw_tucs = (tucs & 0xffff);
+       }
 
        /* Fill in the context descriptor. */
        t = (struct livengood_tcpip_ctxdesc *)