RELENG_7_1: bce driver change generating too much interrupts ?

Since last upgrade, I see much more CPU time "eated" by interrupts (at
least 10% cpu in top)
(see http://dgeo.perso.ec-marseille.fr/cpu-week.png)

The server behave correctly (Or seems to…), and high interrupt number
seems to come from bce cards (source: systat -vmstat)

I just upgraded from
"RELENG_7 Mon Sep 8 12:33:06 CEST 2008"
to
"RELENG_7_1 Sat Nov 29 16:20:35 CET 2008"

We have the same machine (dell PE 1950) which have not been upgraded
(production use - the two machine are carp(4)-redundant)

I don't know if it is related to "SVN rev 184826 on 2008-11-10 22:40:16Z
by delphij" patch to sys/dev/bce/if_bce.c


If I can help debugging something… These are production machines, but I
may test patches or ? on the faulty system.



Some clues:

Under the very same load (carp interfaces down on other machine), vmstat
shows:
for newer system:

procs memory page disk faults cpu
r b w avm fre flt re pi po fr sr mf0 in sy cs us
sy id
0 1 1 4806M 460M 649 0 0 0 582 2 0 21770 1270 13653
1 15 85

and for older:

procs memory page disk faults cpu
r b w avm fre flt re pi po fr sr mf0 in sy cs us
sy id
0 1 0 3694M 414M 236 0 0 0 199 17 0 286 317 386 1
1 97


bce-related part of dmesg for the newer system:

bce0: <Broadcom NetXtreme II BCM5708 1000Base-T (B2)> mem
0xf4000000-0xf5ffffff irq 16 at device 0.0 on pci9
miibus0: <MII bus> on bce0
bce0: Ethernet address: 00:15:c5:f1:56:f4
bce0: [ITHREAD]
bce0: ASIC (0x57081020); Rev (B2); Bus (PCI-X, 64-bit, 133MHz); F/W
(0x02090105); Flags( SPLT MFW MSI )
bce1: <Broadcom NetXtreme II BCM5708 1000Base-T (B2)> mem
0xf8000000-0xf9ffffff irq 16 at device 0.0 on pci5
miibus1: <MII bus> on bce1
bce1: Ethernet address: 00:15:c5:f1:56:f2
bce1: [ITHREAD]
bce1: ASIC (0x57081020); Rev (B2); Bus (PCI-X, 64-bit, 133MHz); F/W
(0x02090105); Flags( SPLT MFW MSI )

And on the older system:

bce0: <Broadcom NetXtreme II BCM5708 1000Base-T (B2)> mem
0xf4000000-0xf5ffffff irq 16 at device 0.0 on pci9
miibus0: <MII bus> on bce0
bce0: Ethernet address: 00:15:c5:f1:6a:47
bce0: [ITHREAD]
bce0: ASIC (0x57081020); Rev (B2); Bus (PCI-X, 64-bit, 133MHz); F/W
(0x02090105); Flags( MFW MSI )
bce1: <Broadcom NetXtreme II BCM5708 1000Base-T (B2)> mem
0xf8000000-0xf9ffffff irq 16 at device 0.0 on pci5
miibus1: <MII bus> on bce1
bce1: Ethernet address: 00:15:c5:f1:6a:45
bce1: [ITHREAD]
bce1: ASIC (0x57081020); Rev (B2); Bus (PCI-X, 64-bit, 133MHz); F/W
(0x02090105); Flags( MFW MSI )

--
Geoffroy Desvernay
Ecole Centrale de Marseille

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