Besides CPU, Harddisk and Bus the capture performance of ethereal
or tcpdump depends heavily on the network card & driver and wether you
capture full packets or only the packet header (first 68 Bytes).
In a test measurement of packet headers with a peak rate of 12000 packets/s
we have seen packet loss of 6*10^-5. Two similar machines showed 8*10-6.
We tested "Intel Ether Express Pro 100" against "DECchip 21140" (Tulip) on an IDE
PIII 550, 384 RAM. With a constant packet rate of 2000/s Intels card could capture
packet headers of short packets but suffered packet loss when capturing headers
from larger packets. The Tulip card showed no losses here. When capturing full
packets, the Intel chip lost up to 35% (1500 Bytes) and the Tulip chip showed
loss of 0.04% or packets larger than 600. This is just to show that network card
& driver has a large influence on your outcome. Also: max granularity of timestamps
is 10 microseconds, may be more.
Maybe that helped,
Regards,
Johannes
On Wednesday, 1. May 2002 14:27, you wrote:
> Sorry, I just resend this email, to know if somebody has answers to my
> question.
>
> Regards,
>
> Syari Mujahid
>
> > -----Original Message-----
> > From: Mujahid Syari
> > Sent: mercredi, 24. avril 2002 16:10
> > To: ethereal-users@xxxxxxxxxxxx
> > Subject: [Ethereal-users] What is the peak limit for Ethereal ?
> >
> > Hi there,
> >
> > I am currently testing the Ethereal on the Linux machine to know the
> > limit of Ethereal (I am using tethereal). At certain level I could
> > see that Ethereal (or maybe on the kernel level) discards some
> > packets. When we reached 2.0 Mbyte per second (I use gkrellm on the
> > source machine), that's when I saw that it discards lots of packets.
> > I am using Pentium 4 1.7 Ghz with 512 Mb SDRAM 133 Mhz. The network
> > card is 3COM Fast EtherLink 10/100. Maybe I have done something
> > wrong (or my number is wrong) somewhere, but
> >
> > My questions are :
> >
> > * Has anybody done a benchmark already for Ethereal.
> > * If yes what machine are you using (CPU speed, RAM, OS, etc.) and
> > what is the peak limit for the ethereal before it discards packets.
> > * Anybody could tell me what I could do to tweak Linux to make it
> > runs faster (a part from killing all those unnecessaries processes)
> > or maybe a site that I could visit.
> >
> _______________________________________________
> Ethereal-users mailing list
> Ethereal-users@xxxxxxxxxxxx
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--
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Johannes Faerber faerber@xxxxxxxxxxxxxxxxxxxx