On Mon, 11 Dec 2000, Graham Stoney wrote: > Hi Brian, > > On Thu, Dec 07, 2000 at 12:11:07PM -0600, Brian Ford wrote: > > I am trying to do some kernel profiling on my EST8260 to determine the > > bottle neck in TCP and UDP thruput, but I can't seem to get any profile > > information. > > When I first attempted a similar thing with the 2.2 kernel on our 855T based > board, I found that the trivial do_profile routine needed to collect data for > /proc/profile kernel profiling wasn't implemented for the ppc architecture. > As far as I can see, it still isn't implemented on linux-2.4.0-test11, but it > is in the linuxppc_2_3 tree at http://www.fsmlabs.com/linuxppcbk.html . > I really wish the seperate architecture maintainers had got together to > eliminate all the duplicated do_profile functions like I did in my 2.2 patch > at: > http://members.nbci.com/greyhams/linux/patches/2.2/profile.patch > > Unfortunately I guess it was easier for the PPC guys to just copy the > do_profile function (yet again!) like everyone else did. Oh well, maybe in > 2.5... > Thanks. I did get it to work with the bitkeeper sources. My problem was that the grep command that produced the System.map file didn't get along with Solaris grep.
I agree with you about the profiling stuff. Did you post this idea to the main kernel mailing list? Maybe that would be the place to tackle this issue. > Back to TCP, I found I could improve raw TCP throughput by 15-20% on the 855T > by DMAing received data directly into the kernel socket buffers. The > improvement in performance from eliminating the extra copy between the ring > buffer and socket buffer isn't staggering, since the CPU still needs to do > a pass through the data to calculate the IP checksum, which unfortunately the > 855T's FEC can't do for me. Nevertheless, it does make things a little faster > and I would imagine a similar technique would work on the 8260; you can get a > feel for what is involved from my 2.2 FEC speedup patch at: > http://members.nbci.com/greyhams/linux/patches/2.2/fecdmaskb.patch > Thanks. I had already hacked something like this together. It would be great to finalize these and get them into the real sources. I also turned checksumming off for testing purposes. It helped some, but I think my bottle neck is that I can't get the bus to run faster than 33 Mhz reliably. If I could get the bus clocked at what it is rated, I might be better off. I don't think the 8260 CPM can do the checksums either. Pitty. It seems like there is plenty of power in there. -- Brian Ford Software Engineer Vital Visual Simulation Systems FlightSafety International Phone: 314-551-8460 Fax: 314-551-8444 ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/
