Sudden mbuf demand increase and shortage under the load (igb issue?)

[Maxim Sobolev]

Folks,

Indeed, it looks like igb(4) issue. Replacing the card with the 
desktop-grade em(4)-supported card has fixed the problem for us. The 
system has been happily pushing 110mbps worth of RTP traffic and 2000 
concurrent calls without any problems for two days now.

em0 at pci0:7:0:0: class=0x020000 card=0xa01f8086 chip=0x10d38086 rev=0x00 
hdr=0x00
     vendor     = 'Intel Corporation'
     class      = network
     subclass   = ethernet

em0: <Intel(R) PRO/1000 Network Connection 6.9.6> port 0xec00-0xec1f mem 
0xfbee0000-0xfbefffff,0xfbe00000-0xfbe7ffff,0xfbedc000-0xfbedffff irq 24 
at device 0.0 on pci7
em0: Using MSIX interrupts
em0: [ITHREAD]
em0: [ITHREAD]
em0: [ITHREAD]
em0: Ethernet address: 00:1b:21:50:02:49

I really think that this has to be addressed before 7.3 release is out. 
FreeBSD used to be famous for its excellent network performance and it's 
shame to see that deteriorating due to sub-standard quality drivers. 
Especially when there is a multi-billion vendor supporting the driver in 
question. No finger pointing, but it really looks like either somebody 
is not doing his job or the said vendor doesn't care so much about 
supporting FreeBSD. I am pretty sure the vendor in question has access 
to numerous load-testing tools, that should have catched this issue.

This is the second time during the past 6 months I have issue with the 
quality of the Intel-based drivers - the first one is filed as 
kern/140326, which has stalled apparently despite me providing all 
necessary debug information.

Regards,
-- 
Maksym Sobolyev
Sippy Software, Inc.
Internet Telephony (VoIP) Experts
T/F: +1-646-651-1110
Web: http://www.sippysoft.com
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