Strange CPU distributionat very high level bandwidth
phoemix at harmless.hu
Wed Aug 19 11:14:00 UTC 2009
Just a question. May I ask how many pps is this traffic (packet per
second). Forward performance actually depends on the pps rate and not
on the bandwidth usage as far as my experience goes. As I've calculated
by your given data, it might be around 166Kpps, but i might be wrong
On Wed, 19 Aug 2009 12:13:37 +0200
Invernizzi Fabrizio <fabrizio.invernizzi at telecomitalia.it> wrote:
> Hi all
> i am going on with some performance tests on a 10gbe network card
> with FreeBSD.
> I am doing this test: I send UDP traffic to be forwarded to the other
> port of the card on both the card ports. Using 1492-long packets i am
> uppering the number of packets per second i sent In order to see
> wich is the maximum bandwidth (or pps) the system can support without
> The limit seems to be about 1890Mbps per port (3870 Mbps total).
> Looking more in deep the CPU behaviour i see this :
> - uppering the sent pps results in uppering the intterrupt time
> (about 90%)
> - when i am very strict to the limit, interrupt time falls to about
> 10% and CPU is always (85%) in system (rx/tx driver procedure)
> - Is not the AIM intended to contrast this behaviour to limit
> interrupts sent to CPU? (nothing changes if i disable it)
> - Why does the system start loosing pkts in that condition?
> - Why does the system seem to perform better when it is managing more
> context switches?
> These are my system details:
> - HP 380 G5 (XEON X5420, CPU speed: 2.50GHz, BUS speed: 1333 MHz, L2
> cache size: 12 MB, L2 cache speed: 2,5 GHz) with 1 quad-core
> - Network card: Silicom PE10G2i-LR - Dual Port Fiber (LR) 10 Gigabit
> Ethernet PCI Express Server Adapter Intel(r) based (chip 82598EB).
> - FreeBSD 7.2-RELEASE (64 bit)
> Driver ixgbe-1.8.6
> dev.ix.0.low_latency: 128
> dev.ix.0.ave_latency: 400
> dev.ix.0.bulk_latency: 1200
> dev.ix.1.low_latency: 128
> dev.ix.1.ave_latency: 400
> dev.ix.1.bulk_latency: 1200
> Telecom Italia
> Fabrizio INVERNIZZI
> Technology - TILAB
> Accesso Fisso e Trasporto
> Via Reiss Romoli, 274 10148 Torino
> Tel. +39 011 2285497
> Mob. +39 3316001344
> Fax +39 06 41867287
> Questo messaggio e i suoi allegati sono indirizzati esclusivamente
> alle persone indicate. La diffusione, copia o qualsiasi altra azione
> derivante dalla conoscenza di queste informazioni sono rigorosamente
> vietate. Qualora abbiate ricevuto questo documento per errore siete
> cortesemente pregati di darne immediata comunicazione al mittente e
> di provvedere alla sua distruzione, Grazie.
> This e-mail and any attachments is confidential and may contain
> privileged information intended for the addressee(s) only.
> Dissemination, copying, printing or use by anybody else is
> unauthorised. If you are not the intended recipient, please delete
> this message and any attachments and advise the sender by return
> e-mail, Thanks.
> [cid:00000000000000000000000000000001 at TI.Disclaimer]Rispetta
> l'ambiente. Non stampare questa mail se non ? necessario.
Harmless Digital Bt
More information about the freebsd-performance