Date: Thu, 24 Mar 2005 09:20:11 -0800 (PST) From: Boris Spirialitious <hardcodeharry@yahoo.com> To: jason henson <jason@ec.rr.com>, freebsd-questions@freebsd.org Subject: Re: AMD64 much slower than i386 on FreeBSD 5.4-pre Message-ID: <20050324172011.50393.qmail@web90207.mail.scd.yahoo.com> In-Reply-To: <424256E6.5030301@ec.rr.com>
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--- jason henson <jason@ec.rr.com> wrote: > em1897@aol.com wrote: > > > > > > >> The answer, Boris, is that the "team" has no idea > what > >> they're doing. Check out some of the threads on > >> performance testing. They tune little pieces here > > >> and there, and break 10 other things in the > process. > >> Matt Dillon "determined" that 10,000 ints/second > >> was "optimal". Of course if you're passing 10Kpps > > >> that means you get an interrupt for every > >> packet. > >> > >> They're playing pin the tail on the donkey. > >> > > > > You could understand what he was saying? I wanted > to help but was > > unsure of what he was asking. I also seem to > remember that discussion > > you are referring too. IIRC, 10,000hz for pooling > was the setting they > > ere talking about. But on it would very a little, > and with the fxp > > based card polling hurt a little because the card > was already ding its > > own thing in hardware. So that setting was > redundant, it was best to > > leave it alone. > > He also seemed to say the network bandwidth was > constant, and system > > load rose with an 64bit system. This right? If he > was using GENERIC on > > a smp system he was only using 1 cpu with out a > recompile. There is > > just so much that could be wrong and he gives no > information on his > > system or settings. > > Doess he have 2 amd64 pcs with 2 different > installs of 5.3, or a > > single machine that he ran both versions on? The > router, is that a > > third machine that was an amd64 system, or > something else? He says > > i386, but an up to date 5.3 world doesn't support > 386 with out a work > > around. The least commom setting is now 486, but a > build for 686 would > > be better. Did he tell you if he had polling on? > > > > So I guess it is a good thing you were able to > help him, because I > > couldn't. Not to mention the flame bait you > through out, well, that > > would be wrong. > _______________________________________________ > > > > --------- Previous Message > > > > No, thats not what I was talking about. They were > tuning the MAX_INTS > > parameter for the em > > driver, which can hold off interrupts to reduce > system overhead. > > Instead of minimizing the load, > > they were focused on squeezing a few extra bits > out of iperf, which is > > not how you tune > > performance. If you get 700Kb/s and have a 95% > load and can get > > 695Kb/s with 60% load, > > which is better? Plus they were testing with a > regular PCI bus, so > > they were hitting the > > wall on the bus throughput, which changes all the > timings, so it was > > just a stupid test in > > general. > > > I would say 60% load. Now I completely understand > what you were saying. > > > > > I'm not 100% sure of what he was saying, but I've > seen the same thing. > > I take an i386 disk > > and pop on an amd64 disk with the same settings, > except for the 3 or 4 > > required differences, > > and the i386 machine has WAY less network load. So > maybe your > > buildworld runs faster, > > but the whole interrupt/process switching > mechanism runs like crap, so > > you likely have a > > slower machine. I haven't seen any test that shows > otherwise, just a > > bunch of swell > > guys swearing that one thing is faster than > another. > > > > I understand that you don't want to hear the > truth, so flame away. But > > its not going to make > > things any better. > > Ahh! More flame bait! I just didn't like you > platitudinal and > unproductive message that I believe would just drive > Boris onto linux > and leave a possible open problem on FreeBSD for > some one else to > discover latter. It's not that I don't want to hear > the truth, you were > just not saying anything worth his time. But > atleast now we can get > some where to help him and the amd64 port. I also > had the idea that > Boris was just trolling because he has not > responded, just said FreeBSD > was bad and left us to duke it out. > > > _______________________________________________ > > freebsd-questions@freebsd.org mailing list > > > http://lists.freebsd.org/mailman/listinfo/freebsd-questions > > To unsubscribe, send any mail to > > "freebsd-questions-unsubscribe@freebsd.org" > > > So the whole interrupt/process switching mechanism > runs like crap with > the amd64 build? Since I don't have a amd64 system, > and you might hav > access to atleast 1, how about getting a little info > on the irqs? Look > at systat -vmstat or vmstat -i under load? aybe > report it back? I > wonder if the irq rates are changing, or irqs are > taking longer to > service. Either there is a problem. Ofcourse some > hardware info would > be nice, chipset and cpu? Maybe you script vmstat > -i for a log, and use > netperf too? > > I like Nick's followup. I would guese Boris may > have a problem with > proper hardware support. I can't really said it is > bad hardware if > speeds are the same, just high load(right?). Maybe > the driver he is > using is not good for 64bit as it is for 32bit? > > I think if Boris studies the thread I like to below > he will be alright. > > Check this out: > http://www.atm.tut.fi/list-archive/freebsd-stable/thrd66.html > http://docs.freebsd.org/cgi/mid.cgi?200502171636.10361.drice > > Inparticular: > http://www.atm.tut.fi/list-archive/freebsd-stable/msg19651.html > http://www.atm.tut.fi/list-archive/freebsd-stable/msg19679.html > I always use systat -vmstat 1 to monitor usage. I also know to set MAX_INTS in if_em.c file. I use 8000 for both tests. I try with broadcom NICs soon. Boris __________________________________ Do you Yahoo!? Yahoo! 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