Messages in this thread | | | Subject | Re: TCP/IP Speed | From | Terje Eggestad <> | Date | 31 Jan 2002 17:06:40 +0100 |
| |
tor, 2002-01-31 kl. 16:26 skrev Richard B. Johnson: > On 31 Jan 2002, Terje Eggestad wrote: > > > Hmmm, > > > > I tend to use the rdtsc register to do these kind of measurements, > > but I get ~110 uS round trip with or without TCP_NDELAY > > > > AMD-SC520 ( 'i486 ) don't have such an instruction. Therefore benchmarks, > which have to run 'everywhere' need to be generic. >
too bad...
> > I get ~100uS wehen pinging with raw ethernet frames. > > > > > PS: Intel 82557 Ethernet Pro 100 NIC's > > > > Ping doesn't count. ICMP is handled in the kernel a few procedures > removed from actual frame acquisition. It looks like the kernel > takes the data I'm waiting for, hides it away for awhile, scheduling > other tasks, then finally decides to wake me up, having been sleeping > in read() for a whole millisecond. This is entirely unacceptable. >
Actually, my "ping" is even less than icmp. I open the ethX with family = AF_PACKET, and provide the full 802 frame.
> Since this 1000 data-buffers-per-second limitation is independent of > CPU speed and/or RAM speed, it seems to be imposed artificially by > the network implementation. It may have something to do with additions > to stop DOS or whatever. I need to turn it OFF. >
Hmmm, guess I haven't tried abutally sending 1000 writes. If you send my you test program, I could try it on my HW's tomorrow.
> I have done setsockopt(s, IPPROTO_TCP, TCP_NODELAY, &x sizeof(x)); > ... SOL_TCP, TCP_NODELAY... > with int x = 1;, everywhere a socket is created. It seems like a > no-op. > > My sun uses SunOS 5.5.1, with GNU 'C' runtime libraries, gcc 2.7.2, and > it doesn't display this problem. The speed is lower because it has only > a 10-base network connection, but the Tx/Rx time is running around > 250 to 300 microseconds, not the awful 1 millisecond. > > > Cheers, > Dick Johnson > > Penguin : Linux version 2.4.1 on an i686 machine (797.90 BogoMips). > > I was going to compile a list of innovations that could be > attributed to Microsoft. Once I realized that Ctrl-Alt-Del > was handled in the BIOS, I found that there aren't any. > -- _________________________________________________________________________
Terje Eggestad mailto:terje.eggestad@scali.no Scali Scalable Linux Systems http://www.scali.com
Olaf Helsets Vei 6 tel: +47 22 62 89 61 (OFFICE) P.O.Box 150, Oppsal +47 975 31 574 (MOBILE) N-0619 Oslo fax: +47 22 62 89 51 NORWAY _________________________________________________________________________
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |