Author: np
Date: Mon Feb 3 23:30:39 2020
New Revision: 357476
URL: https://svnweb.freebsd.org/changeset/base/357476
Log:
cxgbe(4): Do not use pack boundary > 512B unless it is explicitly
requested.
This is a tradeoff between PCIe efficiency during large packet rx and
packing efficiency during small packet rx.
MFC after: 1 week
Sponsored by: Chelsio Communications
Modified:
head/sys/dev/cxgbe/t4_sge.c
Modified: head/sys/dev/cxgbe/t4_sge.c
==============================================================================
--- head/sys/dev/cxgbe/t4_sge.c Mon Feb 3 23:25:12 2020 (r357475)
+++ head/sys/dev/cxgbe/t4_sge.c Mon Feb 3 23:30:39 2020 (r357476)
@@ -589,6 +589,9 @@ t4_sge_extfree_refs(void)
return (refs - rels);
}
+/* max 4096 */
+#define MAX_PACK_BOUNDARY 512
+
static inline void
setup_pad_and_pack_boundaries(struct adapter *sc)
{
@@ -635,7 +638,10 @@ setup_pad_and_pack_boundaries(struct adapter *sc)
pack = fl_pack;
if (fl_pack < 16 || fl_pack == 32 || fl_pack > 4096 ||
!powerof2(fl_pack)) {
- pack = max(sc->params.pci.mps, CACHE_LINE_SIZE);
+ if (sc->params.pci.mps > MAX_PACK_BOUNDARY)
+ pack = MAX_PACK_BOUNDARY;
+ else
+ pack = max(sc->params.pci.mps, CACHE_LINE_SIZE);
MPASS(powerof2(pack));
if (pack < 16)
pack = 16;
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