Re: An interesting anomaly in NFS client...

On 6 Nov 2024, at 21:28, 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 put 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-to-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.
>

15,000 of them?  Seems excessive for a kernel module of 10 files, but maybe it's walking /usr/obj ?

Best,
George