Re: smaller blocksizes with solaris

[Kevin G. <kg...@nc...>]

This was answered not more than a week ago:
On Thu, Apr 08, 2004 at 01:34:41PM -0400, jesse butler wrote:
> Good thought, but not quite on.  I'm running Solaris, which doesn't much 
> care what your buffer size is.
> There is this peice of code in Settings.cpp, though:
> 
>    case 'w': // TCP window size (socket buffer size)
>    mTCPWin = (long) byte_atof( optarg );
>    if ( mTCPWin < 2048 ) {
>        printf( warn_window_small, mTCPWin );
>    }
>    break;
> 
> So, now I'd like to snip this bit and rebuild, but am not sure if that 
> will affect operation at all.  If anyone has any warnings, please let me 
> know.  In that case, I'll have to go back to ttcp.

 *sigh*  That's what I get for not actually checking the code.  I'm not 
sure why that's there.  

  At any rate, removing that check won't hurt anything and will give you 
the desired behavior.

Kevin


On Mon, 12 Apr 2004, jesse butler wrote:

> Hi,
> 
> As communicated earlier, I'm having some trouble using small blocksizes 
> with Iperf.  As shown below, I attempt to use 16 bytes, but after the 
> warn, it is set to 32 KB.
> 
> [jesseb@aion]: ~/iperf/iperf-1.1.1 $ iperf -c aion -w 16
> WARNING: TCP window size set to 16 bytes. A small window size
> will give poor performance. See the Iperf documentation.
> ------------------------------------------------------------
> Client connecting to aion, TCP port 5001
> TCP window size: 32.0 KByte (WARNING: requested 16.0 Byte)
> ------------------------------------------------------------
> [  4] local 129.148.184.208 port 36483 connected
> 
> 
> I would like to change the code and rebuild so it will work for me, but 
> am a bit stuck.  I've discovered that at some point, a small blocksize 
> is getting overridden with a larger size, but I can't find where in the 
> code.  I have traced it into lib/tcp_window_size.c and 
> setsock_tcp_windowsize(), which in turn calls setsockopt()... but I 
> don't see anywhere where if the window size passed in is overridden if 
> it's smaller than a certain size.
> 
> Anyone have any ideas, see anything, want to bop me on the head for 
> missing something obvious?
> 
> Thanks,
> Jesse
>