1. OK. That's fair enough. I'll give that ago.
2. Yeah, it also occurs for large values of -n, say 10000.
3. Great.
4. Yeah, the times are small as I'm only doing short runs (-n 1000) to avoid the -32/-104 errors. I'll try pushing -n up a bit.
Thanks Libor,
Steve.
Libor Michalek wrote:
On Tue, Apr 12, 2005 at 09:08:15PM +0100, Steven Wooding wrote:
Hi,
I have been putting ttcp.aio through its paces and have a few questions.
1. When -l is larger than 131072 I get an Event error <-22> on the transmit
side and no data to transferred. Changing values of -n and -a do not make
any difference.
The FMRs need to be sized at initialization time. The code currently picks 128K as the size for the FMRs, and does not support an AIO operation that would span multiple FMRs. If you want to try larger AIO operations with the current code you will need to recompile SDP with a larger FMR size, which is determined by the constant SDP_IOCB_SIZE_MAX in sdp_iocb.h It's been a while since I've last tried this, if you try it and have problems let me know.
2. When using a value of 1 for -a (so I suppose this is non-aio), I get an
Event error of <-32> on the transmit side and an <-104> on the receiver end.
Only some of the data is transferred.
I'll look into this, I'm seeing a problem on longer runs myself. With a value of 1 for -a it still uses aio, the value only means how many aio operations can be outstanding at a given time. This just means that a single buffer will be submitted for read/write and a new one will not be submitted until that buffer's IO completes.
3. For future reference, where can I find out what these Event error codes
mean to give me a glue of what's going wrong.
The errors are errno values. I'll make a note to write up which errors are possible and what they are likely to mean.
4. I sometimes see significant differences in the transfer speed reported on
the transmit and receiver ends. Is one more right than the other?
Are the wall clock times for the data transfers small, on the order of a few seconds? How big of a wall clock time difference are you seeing?
-Libor
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