Date: Thu, 7 Nov 2024 14:44:04 -0800 From: Rick Macklem <rick.macklem@gmail.com> To: Mark Johnston <markj@freebsd.org> Cc: Andriy Gapon <avg@freebsd.org>, freebsd-net@freebsd.org Subject: Re: An interesting anomaly in NFS client... Message-ID: <CAM5tNy62NAVWWNLCr15ov4nWVARwH0xU1Kz-zu7Si5wo4PEUxA@mail.gmail.com> In-Reply-To: <Zy06kX6pJIuMzoFB@nuc> References: <7FFE3D2B-4DD9-4657-ADC1-9C40CB54991F@neville-neil.com> <8187509e-c9fb-403f-8569-28ba58425cff@FreeBSD.org> <Zy06kX6pJIuMzoFB@nuc>
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On Thu, Nov 7, 2024 at 2:09=E2=80=AFPM Mark Johnston <markj@freebsd.org> wr= ote: > > On Thu, Nov 07, 2024 at 07:28:59AM +0200, Andriy Gapon wrote: > > On 07/11/2024 02:43, George Neville-Neil wrote: > > > Howdy, > > > > > > We've been digging into an interesting possible issue in the FreeBSD = NFS > > > client. Here is the scenario. I have a FreeBSD VM on my Mac, the Mac = is > > > the NFS server, the VM is the client. I then attempt to build an out = of > > > tree kernel module that I'm working on. The build looks like it's > > > hanging for 1.5 seconds, and when we look at the packets (pcap file > > > attached) we see a ton of GETATTRs over the first 1.5 seconds. I've p= ut > > > the pcap up here: oct_8_2024.pcapng <https:// > > > people.freebsd.org/~gnn/oct_8_2024.pcapng> > > > > > > I also note that an issue was raised on the forums that seems similar= , > > > way back between FreeBSD 10 and 11: > > > > > > https://forums.freebsd.org/threads/nfs-cache-misses-after-upgrading-t= o-11-1- > > > from-10-3.65491/ > > > <https://forums.freebsd.org/threads/nfs-cache-misses-after- > > > upgrading-to-11-1-from-10-3.65491/> > > > > > > I'm seeing this on 15 currentish (last few months). > > > > Could it be just make checking for stale targets? > > I.e., stat-ing various files to check their timestamps. All I can tell you is that the GETATTRs all check directories (at least all the ones I looked at). They all appear to be different directories. Btw, if you have not already done so, look at the packet trace in wireshark= . It actually knows how to decode NFS. rick > > I suspect it is from this line in sys/conf/config.mk: > > __MPATH!=3Dfind ${SYSDIR:tA}/ -name \*_if.m > > This is running a find command over all of sys/, so it'll stat about > 35000 files. I believe it's from > https://cgit.freebsd.org/src/commit/?id=3D12f05b84463baacfada5a79eaed061a= 4899d98aa >
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