Date: Thu, 20 Jun 2013 10:34:46 +0000 From: "Eggert, Lars" <lars@netapp.com> To: "freebsd-net@freebsd.org" <freebsd-net@freebsd.org> Cc: Jack Vogel <jfvogel@gmail.com> Subject: hw.igb.num_queues default Message-ID: <843F7891-FD87-4F16-A279-B45D4A674F4E@netapp.com>
index | next in thread | raw e-mail
Hi, I just popped a new four-port igb card into a -STABLE system and encountered severe issues even when unloaded right after boot, to the point where I couldn't even ssh into the system anymore. The box has 2x4 cores: CPU: Intel(R) Xeon(R) CPU X5450 @ 3.00GHz (2992.60-MHz K8-class CPU) Origin = "GenuineIntel" Id = 0x10676 Family = 0x6 Model = 0x17 Stepping = 6 Features=0xbfebfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CLFLUSH,DTS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE> Features2=0xce3bd<SSE3,DTES64,MON,DS_CPL,VMX,EST,TM2,SSSE3,CX16,xTPR,PDCM,DCA,SSE4.1> AMD Features=0x20100800<SYSCALL,NX,LM> AMD Features2=0x1<LAHF> TSC: P-state invariant, performance statistics real memory = 8589934592 (8192 MB) avail memory = 8239513600 (7857 MB) MPTable: <DELL PE 01B2 > Event timer "LAPIC" quality 400 FreeBSD/SMP: Multiprocessor System Detected: 8 CPUs FreeBSD/SMP: 2 package(s) x 4 core(s) By default, the igb driver seems to set up one queue per detected CPU. Googling around, people seemed to suggest that limiting the number of queues makes things work better. I can confirm that setting hw.igb.num_queues=2 seems to have fixed the issue. (Two was the first value I tried, maybe other values other than 0 would work, too.) In order to uphold POLA, should the igb driver maybe default to a conservative value for hw.igb.num_queues that may not deliver optimal performance, but at least works out of the box? Larshome | help
Want to link to this message? Use this
URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?843F7891-FD87-4F16-A279-B45D4A674F4E>