Packet loss problem and some questions related with OS

[Benjamin]

  Hi All,

I have some doubts , please clear me.


Query 1 ) should we set irq afinity of pci lan interface or onboard lan 
interface or we can do for both ?

Query 2) H/w must be APIC enabled and for them only we can do set irq 
afinity , is it so?

Query 3) What are the root cause for packet loss on interface ?

Actually in one of my server , i m having strange result, i can not see 
any value update for lan interface in interrupts.

cat /proc/interrupts
            CPU0       CPU1       CPU2       CPU3
   0:        124          0          0         78   IO-APIC-edge      timer
   1:          0          0          0        614   IO-APIC-edge      i8042
   8:          0          0          0          1   IO-APIC-edge      rtc0
   9:          0          0          0          0   IO-APIC-fasteoi   acpi
  12:          0          0          0        159   IO-APIC-edge      i8042
  19:          0      13411          0          0   IO-APIC-fasteoi   
ata_piix, ata_piix
  21:          0          0         70          0   IO-APIC-fasteoi   
ehci_hcd:usb1
  23:          0          0         32          0   IO-APIC-fasteoi   
ehci_hcd:usb2
  40:     229974          0          0          0  HPET_MSI-edge      hpet2
  41:          0      85867          0          0  HPET_MSI-edge      hpet3
  42:          0          0      73987          0  HPET_MSI-edge      hpet4
  43:          0          0          0     106848  HPET_MSI-edge      hpet5
  45:          0          0          0          0   PCI-MSI-edge      
aerdrv, PCIe PME
  46:          0          0          0          0   PCI-MSI-edge      
aerdrv, PCIe PME
  47:          0          0          0          0   PCI-MSI-edge      
PCIe PME
  48:          0          0          0          0   PCI-MSI-edge      
PCIe PME
  49:          0          0          0          0   PCI-MSI-edge      
PCIe PME
  50:          0          0          0     219714   PCI-MSI-edge
  51:      10880          0          0          0   PCI-MSI-edge
_ 52:          4          0          0          0   PCI-MSI-edge      em1_
NMI:         44         16          8         29   Non-maskable interrupts
LOC:        282        248        158         68   Local timer interrupts
SPU:          0          0          0          0   Spurious interrupts
PMI:         44         16          8         29   Performance 
monitoring interrupts
IWI:          0          0          0          0   IRQ work interrupts
RES:       6283       2718       2153       5353   Rescheduling interrupts
CAL:        128        100        228        278   Function call interrupts
TLB:         15         33         12         22   TLB shootdowns
TRM:          0          0          0          0   Thermal event interrupts
THR:          0          0          0          0   Threshold APIC interrupts
MCE:          0          0          0          0   Machine check exceptions
MCP:         78         78         78         78   Machine check polls
ERR:          0
MIS:          0


em1 is my lan interface.

ifconfig
em1       Link encap:Ethernet  HWaddr 00:25:90:0A:E6:A2
           inet addr:192.168.100.152  Bcast:192.168.100.255  
Mask:255.255.255.0
           inet6 addr: fe80::225:90ff:fe0a:e6a2/64 Scope:Link
           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
           RX packets:216457 errors:0 _dropped:16064_ overruns:0 frame:0
           TX packets:12715 errors:0 dropped:0 overruns:0 carrier:0
           collisions:0 txqueuelen:1000
           RX bytes:36976063 (35.2 MiB)  TX bytes:2391031 (2.2 MiB)
_Interrupt:16_ Memory:fb5e0000-fb600000

lo        Link encap:Local Loopback
           inet addr:127.0.0.1  Mask:255.0.0.0
           inet6 addr: ::1/128 Scope:Host
           UP LOOPBACK RUNNING  MTU:16436  Metric:1
           RX packets:0 errors:0 dropped:0 overruns:0 frame:0
           TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
           collisions:0 txqueuelen:0
           RX bytes:0 (0.0 b)  TX bytes:0 (0.0 b)



But i can not see any 16 irq no. in cat /proc/interrupts.

I tried to increase rx and tx for em1 but still same i m having packet 
loss on interface.

OS : fedora 15 64 bit.

04:00.0 Ethernet controller: Intel Corporation 82574L Gigabit Network 
Connection
05:00.0 Ethernet controller: Intel Corporation 82574L Gigabit Network 
Connection

Kernel : 2.6.40.6-0.fc15.x86_64


Please guide me to solve this issues and resolve my queries.


Warm Regards,
Benjamin


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