[c-nsp] High latency/jitter at times on a NPE-G1?

Rodney Dunn rodunn at cisco.com
Thu Jun 1 11:59:57 EDT 2006


On Thu, Jun 01, 2006 at 10:25:26AM -0300, Sean Watkins wrote:
>  
> Hi
> 
> > 
> > If you want to prove it put a sniffer/analyzer on both sides 
> > of the box and time sync the traces.
> 
> Ok good idea. 
> 
> > 
> > That is just about the ONLY way you can 100% prove the box is 
> > introducing latency/jitter in the forwarding stream.
> 
> 
> > 
> > There will always be some latency/jitter but it should be so 
> > small it's irrelevant. 
> > 
> > What order of magnitude are you talking about?
> 
> 300 Ms at times.
> 
> 
> > 
> > TAC will have an extremely hard time solving this problem 
> > unless you can prove with a trace when and how much latency 
> > the box is really introducing.
> 
> 
> > 
> > I'd be very amazed if it's the 72xx because it's software 
> > forwarding and once the packet goes in the switching vector 
> > it can't be held up other than if there is congestion for the 
> > most part.
> 
> Interesting. I figured as the box is software forwarding, it was open to a
> whole host latency issues? 

The latency without congestion should be minimal. You are talking about
forwarding latency through the box which should be sub 50 msec I'd guess.
I've never tested it in the lab but I'm sure it's low.

> 
> I've seen at times, on software based platforms, TFTP kill the performance
> of the box? Even with CEF?

That's not right. I think you are confusing things in regards to process
switching of traffic and CEF switching through the box.

> 
> 
> 
> > 
> > Just curious:
> > 
> > can you post a 'sh c7200' output.
> > 
> 
> Attached below
> 
> 
> Network IO Interrupt Throttling:
>  throttle count=0, timer count=0
>  active=0, configured=0
>  netint usec=4000, netint mask usec=200

Ok..this is what I wanted to make sure of. We are not throttling
network interrupts for some reason so as soon as the packet comes
in the interrupt will be serviced and the packet will be forwarded.


i> 
> Midplane EEPROM:
>         Hardware revision 2.1           Board revision B0
>         Serial number     21298919      Part number    73-3223-05
>         Test history      0x0           RMA number     00-00-00
>         MAC Pool Size     1024          MAC Addr Base  0005.9aee.1000
>         Chassis Model     0x6         
>         EEPROM format version 1
>         EEPROM contents (hex):
>           0x00: 01 06 02 01 01 44 FE E7 49 0C 97 05 00 05 9A EE
>           0x10: 10 00 04 00 00 00 00 00 00 10 30 58 00 00 FF 00
>           0x20: 00 00 00 00 62 DA 42 DC 62 C6 00 00 60 85 C8 00
>           0x30: 62 D3 00 00 00 00 00 00 00 00 00 00 62 DA 42 DC
> 
> C7206VXR CPU EEPROM:
>         Hardware Revision        : 2.1
>         Top Assy. Part Number    : 800-18896-12
>         Part Number              : 73-6988-12
>         Board Revision           : A0
>         PCB Serial Number        : 34615042
>         RMA History              : 00
>         Fab Version              : 09
>         Fab Part Number          : 28-5082-09
>         Product (FRU) Number     : NPE-G1
>         Deviation Number         : 0-0
>         EEPROM format version 4
>         EEPROM contents (hex):
>           0x00: 04 FF 40 03 5B 41 02 01 C0 46 03 20 00 49 D0 0C
>           0x10: 82 49 1B 4C 0C 42 41 30 C1 8B 33 34 36 31 35 30
>           0x20: 34 32 00 00 00 04 00 02 09 85 1C 13 DA 09 CB 86
>           0x30: 4E 50 45 2D 47 31 80 00 00 00 00 FF FF FF FF FF
>           0x40: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
>           0x50: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
>           0x60: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
>           0x70: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
> 
> TLB entries (50/64 used):
> Virt Address range      Phy Address range         Attributes
> 0x4B000000:0x4B1FFFFF   0x14B000000:0x14B1FFFFF   CacheMode=2, RW, Invalid
> 0x4B200000:0x4B3FFFFF   0x14B200000:0x14B3FFFFF   CacheMode=2, RW, Invalid
> 0x10000000:0x10001FFF   0x0FC010000:0x0FC011FFF   CacheMode=2, RW, Valid
> 0x42000000:0x43FFFFFF   0x062000000:0x063FFFFFF   CacheMode=2, RW, Valid
> 0x46000000:0x47FFFFFF   0x066000000:0x067FFFFFF   CacheMode=2, RW, Valid
> 0x3C000000:0x3C7FFFFF   0x068000000:0x0687FFFFF   CacheMode=2, RW, Valid
> 0x3C800000:0x3CFFFFFF   0x068800000:0x068FFFFFF   CacheMode=2, RW, Invalid
> 0x3D000000:0x3D7FFFFF   0x06D000000:0x06D7FFFFF   CacheMode=2, RW, Invalid
> 0x3D800000:0x3DFFFFFF   0x069000000:0x0697FFFFF   CacheMode=2, RW, Valid
> 0x3E000000:0x3E7FFFFF   0x06D800000:0x06DFFFFFF   CacheMode=2, RW, Invalid
> 0x3E800000:0x3EFFFFFF   0x069800000:0x069FFFFFF   CacheMode=2, RW, Invalid
> 0x3F000000:0x3F7FFFFF   0x06E000000:0x06E7FFFFF   CacheMode=2, RW, Invalid
> 0x1FC00000:0x1FC7FFFF   0x01FC00000:0x01FC7FFFF   CacheMode=2, RO, Valid
> 0x1E000000:0x1E7FFFFF   0x01E000000:0x01E7FFFFF   CacheMode=2, RW, Valid
> 0x1E800000:0x1E9FFFFF   0x01E800000:0x01E9FFFFF   CacheMode=2, RW, Valid
> 0x60000000:0x607FFFFF   0x000000000:0x0007FFFFF   CacheMode=5, RO, Valid
> 0x60800000:0x60FFFFFF   0x000800000:0x000FFFFFF   CacheMode=5, RO, Valid
> 0x61000000:0x617FFFFF   0x001000000:0x0017FFFFF   CacheMode=5, RO, Valid
> 0x61800000:0x619FFFFF   0x001800000:0x0019FFFFF   CacheMode=5, RO, Valid
> 0x61A00000:0x61A1FFFF   0x001A00000:0x001A1FFFF   CacheMode=5, RO, Valid
> 0x61A20000:0x61A3FFFF   0x001A20000:0x001A3FFFF   CacheMode=5, RO, Valid
> 0x61A40000:0x61A47FFF   0x001A40000:0x001A47FFF   CacheMode=5, RO, Valid
> 0x61A48000:0x61A4FFFF   0x001A48000:0x001A4FFFF   CacheMode=5, RO, Valid
> 0x61A50000:0x61A57FFF   0x001A50000:0x001A57FFF   CacheMode=5, RO, Valid
> 0x61A58000:0x61A5FFFF   0x001A58000:0x001A5FFFF   CacheMode=5, RW, Valid
> 0x61A60000:0x61A7FFFF   0x001A60000:0x001A7FFFF   CacheMode=5, RW, Valid
> 0x61A80000:0x61AFFFFF   0x001A80000:0x001AFFFFF   CacheMode=5, RW, Valid
> 0x61B00000:0x61B7FFFF   0x001B00000:0x001B7FFFF   CacheMode=5, RW, Valid
> 0x61B80000:0x61BFFFFF   0x001B80000:0x001BFFFFF   CacheMode=5, RW, Valid
> 0x61C00000:0x61DFFFFF   0x001C00000:0x001DFFFFF   CacheMode=5, RW, Valid
> 0x61E00000:0x61FFFFFF   0x001E00000:0x001FFFFFF   CacheMode=5, RW, Valid
> 0x62000000:0x63FFFFFF   0x002000000:0x003FFFFFF   CacheMode=5, RW, Valid
> 0x64000000:0x65FFFFFF   0x004000000:0x005FFFFFF   CacheMode=5, RW, Valid
> 0x66000000:0x67FFFFFF   0x006000000:0x007FFFFFF   CacheMode=5, RW, Valid
> 0x68000000:0x69FFFFFF   0x008000000:0x009FFFFFF   CacheMode=5, RW, Valid
> 0x6A000000:0x6BFFFFFF   0x00A000000:0x00BFFFFFF   CacheMode=5, RW, Valid
> 0x6C000000:0x6DFFFFFF   0x080000000:0x081FFFFFF   CacheMode=5, RW, Valid
> 0x6E000000:0x6FFFFFFF   0x082000000:0x083FFFFFF   CacheMode=5, RW, Valid
> 0x70000000:0x71FFFFFF   0x084000000:0x085FFFFFF   CacheMode=5, RW, Valid
> 0x72000000:0x73FFFFFF   0x086000000:0x087FFFFFF   CacheMode=5, RW, Valid
> 0x74000000:0x75FFFFFF   0x088000000:0x089FFFFFF   CacheMode=5, RW, Valid
> 0x76000000:0x77FFFFFF   0x08A000000:0x08BFFFFFF   CacheMode=5, RW, Valid
> 0x78000000:0x79FFFFFF   0x08C000000:0x08DFFFFFF   CacheMode=5, RW, Valid
> 0x7A000000:0x7BFFFFFF   0x08E000000:0x08FFFFFFF   CacheMode=5, RW, Valid
> 0x0C000000:0x0DFFFFFF   0x00C000000:0x00DFFFFFF   CacheMode=5, RW, Valid
> 0x0E000000:0x0FFFFFFF   0x00E000000:0x00FFFFFFF   CacheMode=5, RW, Valid
> 0x50000000:0x57FFFFFF   0x090000000:0x097FFFFFF   CacheMode=5, RW, Valid
> 0x58000000:0x5FFFFFFF   0x098000000:0x09FFFFFFF   CacheMode=5, RW, Valid
> 0x20000000:0x27FFFFFF   0x0C0000000:0x0C7FFFFFF   CacheMode=5, RW, Valid
> 0x28000000:0x2FFFFFFF   0x0C8000000:0x0CFFFFFFF   CacheMode=5, RW, Valid
> It is normal operation to have both Valid and Invalid TLB entries.
> 
> 
> System was restarted by power-on at 22:14:02 UTC Sun Apr 9 2000 
> 0 spurious cache errors detected.
> 
> 
> System Controller Network Interrupts
>  Wrapper is INSTALLED at address 0x60864730
>  Interrupt Register is at 0xB0020040 (0x0000000000000000)
> 
> Registered Interrupts:
>  Level Mask               Count      Data       Interrupt Handler
>  0     0x0000000000200000 0          0x500564FC 0x6015E3E8
> (GigabitEthernet0/3)
>  0     0x0000000000100000 216336     0x50044540 0x6015E3E8
> (GigabitEthernet0/2)
>  0     0x0000000000080000 2299926    0x62D56430 0x6015E3E8
> (GigabitEthernet0/1)
>  1     0x0000000800000000 7          0x00000000 0x6015EAB8 (SBETH media
> interrupt)
>  1     0x0000000000001000 690        0x00000000 0x60864BC8 (BCM-1250 PCMCIA)
>  2     0x0000000000000020 0          0x62D43690 0x6086505C (SB1250 Timer 3)
>  2     0x0000000000000010 0          0x62D435E0 0x6086505C (SB1250 Timer 2)
>  2     0x0000000000000008 0          0x62D43530 0x6086505C (SB1250 Timer 1)
>  2     0x0000000000000004 0          0x62D43480 0x6086505C (SB1250 Timer 0)
>  4     0x007C00000000E0C3 0          0x00000000 0x60883DEC (Spurious Intr
> ERROR Handler)
>  4     0x0000000000020000 0          0x00000000 0x6088391C (Corrected ECC
> Error Handler)
>  4     0x0000000000010000 0          0x00000000 0x60883594 (Bad ECC Error
> Handler)
>  4     0x0000003000000000 0          0x00000000 0x60864BE4 (Sturgeon Error
> Handler)
>  4     0x0003000000000000 0          0x627119BC 0x608839A4 (BCM1250 Host LDT
> Bridge Error Handler)
>  4     0x0000000000040000 0          0x00000000 0x60883C60 (BCM1250 IO-Bus
> Error Handler)
>  4     0x0080000000000000 0          0x00000000 0x60883A2C (BCM1250 Host PCI
> Bridge Error Handler)


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