Date: Thu, 16 Dec 1999 20:55:54 -0700 From: "Kenneth D. Merry" <ken@kdm.org> To: Matthew Dillon <dillon@apollo.backplane.com> Cc: Andrew Gallatin <gallatin@cs.duke.edu>, Kevin Day <toasty@dragondata.com>, Poul-Henning Kamp <phk@critter.freebsd.dk>, freebsd-current@FreeBSD.ORG Subject: Re: Serious server-side NFS problem Message-ID: <19991216205554.A20410@panzer.kdm.org> In-Reply-To: <199912170328.TAA57721@apollo.backplane.com>; from dillon@apollo.backplane.com on Thu, Dec 16, 1999 at 07:28:34PM -0800 References: <199912160758.BAA87332@celery.dragondata.com> <199912160801.AAA50074@apollo.backplane.com> <14425.33053.359447.429215@grasshopper.cs.duke.edu> <199912170328.TAA57721@apollo.backplane.com>
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On Thu, Dec 16, 1999 at 19:28:34 -0800, Matthew Dillon wrote: > :Matthew Dillon writes: > : > : > We're already testing a patch. > : > :Thanks again Matt! > : > :The latest rev of nfs_serv.c has fixed it. > : > :I'm now seeing FreeBSD UDP client read bandwidth of 9.2MB/sec & write > :bandwidth of 10.9MB/sec. Solaris clients are writing over TCP at > :10.1MB/sec (and that is across a router!) and are reading at 7MB/sec. [ ... ] > :Andrew Gallatin, Sr Systems Programmer http://www.cs.duke.edu/~gallatin > :Duke University Email: gallatin@cs.duke.edu > > Those are really quite excellent results! Linux eat your heart out! I > get 9.5 to 10.5 MBytes/sec on my half-duplex network between two fast > machines. I tend to get between 7.5 and 9 MBytes/sec when using slower > (200-300 MHz) clients. That's *with* packet loss (for some reason when > my fxp ethernets pump data out that quickly they tend to cause packet > loss in other parts of my HUBed network, which I find quite annoying). > > We've solved most of the performance issues, but NFS is still > eating a little too much cpu for my tastes. Unfortunately it is getting to > the point where a significant portion of the performance loss is occuring > in the network driver itself. Some of my cards eat 25% of the cpu just > in 'interrupt' (at 10 MBytes/sec half duplex), not even counting the > TCP or UDP stacks. This is mainly due to the MTU being too small (i.e. > packet fragmentation takes it toll on the interrupt subsystem). SCSI > cards are way ahead of NIC cards in regards to reducing interrupt > overhead (though gigabit NICs have caught up some). Another advantage with gigabit ethernet is that if you can do jumbo frames, you can fit an entire 8K NFS packet in one frame. I'd like to see NFS numbers from two 21264 Alphas with GigE cards, zero copy, checksum offloading and a big striped array on one end at least. I bet you could get pretty good performance with a setup like that. (Now don't anybody go out and do it unless you really want to spend the time.) Ken -- Kenneth Merry ken@kdm.org To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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