Hi!
On 18:37 Tue 21 Apr , Devesh Sharma wrote:
> Hello michi, Sorry for late reply. comments are inline:
...
> > Is there any packet loss on the link? What does "ping -f" and
> packet loss is very less......after data transfer in TBits I observer
> on 5 tx packet drops
> > "ping -f -s 4096" say? How much does the latency increase if you send
> > bigger packets? Is there a "magic value" which causes a "sudden increase"
> > (e.g. 4051 is much slower than 4050)?
> Yes there is a magic number for packet size of 4040 bytes in ping -s
> 4040 gives proper results
> but of ping -s 4041 every alternate packet get delayed upto 1000 ms.
This is interesting:
Ethernet header is 14 byte + 4 byte crc32 (you said, you are using something
else, do you know the header/trailer size?)
IP header is 20 byte
UDP header is 8 byte (what prococol are you using?)
---
54 bytes
4040+54 = 4094
This is very close to the 4096 page size most machines have. But 1000 ms for
a 8KB continuous memory allocation on a machine with 64GB RAM sounds pretty
extreme. Maybe oprofile has has clues or there was a regression and older
kernels run faster?
-Michi
--
programing a layer 3+4 network protocol for mesh networks
see http://michaelblizek.twilightparadox.com
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