truss or dtrace the ttcp process which is pulling data from a file, and compare that with the results of truss/dtrace of the ttcp process using internally created data. You might also try sending the data from a ramdisk, although I don't think it'll be terribly different from the internally generated case. However, you add file system semantics to the mix and can see if those are related to the problem you are experiencing.
My general findings in comparisons of Linux vs. Solaris is that Solaris is coded (and designed) for correctness first. Linux is coded for speed first. Which is all good and fine if the data isn't important. So something Solaris is doing, possibly at the file system level, is slowing down your transfers, and it's likely a feature that is designed to promote correctness and safety. You can probably disable it and see speed increases on your Solaris system comparable to your Linux system. On Fri, May 14, 2010 at 18:06, Ken Mandelberg <[email protected]> wrote: > I've done some more testing, and have narrowed down the problem a bit. > > Again this issue is specific to my Clearwire 10Mbit bandwidth, 100ms > latency connection. I had originally been doing scp transfers for testing. > Linux gets the full 10mbits, any Solaris 10 machine I tried only got a small > fraction of that. > > I started using other tests, "iperf" and "ttcp" which send an internally > generated set of data and do timings. These get the full 10mbits on both > Solaris and Linux. > > ttcp also has an option to take the data it sends from a file. Using this > option Linux stays at 10mbits, and Solaris goes back down to a small > fraction. Looking at the modem lights at the destination, I see the flashing > stop every few seconds for the Solaris send from a file. In all the other > cases it flashes continuously. > > So I presume the extra context switch to read the data from a file is > causing some disruption of the tcp windowing protocol that ordinarily covers > the high latency ack's. For some reason this doesn't happen on Linux. > > Any thoughts? > -- > This message posted from opensolaris.org > _______________________________________________ > networking-discuss mailing list > [email protected] > -- "You can choose your friends, you can choose the deals." - Equity Private "If Linux is faster, it's a Solaris bug." - Phil Harman Blog - http://whatderass.blogspot.com/ Twitter - @khyron4eva
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