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* PF_PACKET: packets out of order 
@ 2001-10-08 23:32 Joerg Schumacher
  2001-10-08 23:43 ` David S. Miller
  0 siblings, 1 reply; 3+ messages in thread
From: Joerg Schumacher @ 2001-10-08 23:32 UTC (permalink / raw)
  To: linux-kernel

Hi!

NeTraMet v44b10 uses pcap(3) and complains about timestamps jumping 
backwards.  Looks like a PF_PACKET socket doesn't receive the packets 
in the correct order.  Some timestamps from a "tcpdump -tt":

   RX:  1001465480.175100 [...] 
   TX:  1001465480.179111 [...] 
   RX:  1001465480.177315 [...] 
                   ^^^^^^
   TX:  1001465480.180514 [...]
   RX:  1001465480.179706 [...]
	   
Some more figures (obtained with a quick hack using libpcap-2001.09.25 
on two different machines):

   2.2.19:
        stats:    100000 packets received
                       0 packets dropped
        good:      90222 packets
        bad:        9778 packets
        max delta: 15850 usec

   2.4.1:
        stats:    100000 packets received
                       0 packets dropped
        good:      99538 packets
        bad:         462 packets
        max delta:   471 usec
    
Any plans to fix this in the kernel?  


Regards,
Joerg 

-- 
 Gaertner Datensysteme                         38114 Braunschweig 
 Joerg Schumacher                              Hamburger Str. 273a
 Tel: 0531-2335555                             Fax: 0531-2335556

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: PF_PACKET: packets out of order 
  2001-10-08 23:32 PF_PACKET: packets out of order Joerg Schumacher
@ 2001-10-08 23:43 ` David S. Miller
  2001-10-09  1:43   ` Joerg Schumacher
  0 siblings, 1 reply; 3+ messages in thread
From: David S. Miller @ 2001-10-08 23:43 UTC (permalink / raw)
  To: schuma; +Cc: linux-kernel

   From: Joerg Schumacher <schuma@gaertner.de>
   Date: Tue, 9 Oct 2001 01:32:16 +0200 (MET DST)

   Hi!
   
   NeTraMet v44b10 uses pcap(3) and complains about timestamps jumping 
   backwards.  Looks like a PF_PACKET socket doesn't receive the packets 
   in the correct order.  Some timestamps from a "tcpdump -tt":
   
      RX:  1001465480.175100 [...] 
      TX:  1001465480.179111 [...] 
      RX:  1001465480.177315 [...] 
                      ^^^^^^
      TX:  1001465480.180514 [...]
      RX:  1001465480.179706 [...]

The receive packets are in order, as are the transmit packets.

Anything which absolutely _requires_ all TX and RX packets to
be in precise order, should really be fixed not to have such
a weird restriction.

Franks a lot,
David S. Miller
davem@redhat.com

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: PF_PACKET: packets out of order
  2001-10-08 23:43 ` David S. Miller
@ 2001-10-09  1:43   ` Joerg Schumacher
  0 siblings, 0 replies; 3+ messages in thread
From: Joerg Schumacher @ 2001-10-09  1:43 UTC (permalink / raw)
  To: David S. Miller; +Cc: linux-kernel

On Mon, Oct 08, 2001 at 04:43:37PM -0700, David S. Miller wrote:
> [...]
> Anything which absolutely _requires_ all TX and RX packets to
> be in precise order, should really be fixed not to have such
> a weird restriction.

Do humans qualify as "anything" ;-)?  Until I saw the "LastTime jump
backward" warning in netramet I used to read the tcpdump output line 
by line without checking the timestamps.   Neither packet(7) nor 
tcpdump(1) indicate that I should do so. 

Regards, 
Joerg.

-- 
 Gaertner Datensysteme                         38114 Braunschweig 
 Joerg Schumacher                              Hamburger Str. 273a
 Tel: 0531-2335555                             Fax: 0531-2335556

^ permalink raw reply	[flat|nested] 3+ messages in thread

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2001-10-08 23:32 PF_PACKET: packets out of order Joerg Schumacher
2001-10-08 23:43 ` David S. Miller
2001-10-09  1:43   ` Joerg Schumacher

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