MJ a écrit : > > > On 28/02/2026 8:16 pm, BERTRAND Joël wrote: >> MJ a écrit : >>> >>> >>> On 28/02/2026 8:21 am, BERTRAND Joël wrote: >>>> Michael van Elst a écrit : >>>>> joel.bertrand%systella.fr@localhost (=?UTF-8?Q?BERTRAND_Jo=c3=abl?=) writes: >>>>> >>>>>> CPU is an i7-4770, main memory 16 GB. This server exports >>>>>> /srv and >>>>>> /home through NFS (V3/TCP, 128 threads, async) and disk I/O from NFS >>>>>> clients are very slow. Server load can raise until 110 or 120 during >>>>>> huge NFS access. >>>>> >>>>> Can you quantify what "slow" means? Any kind of benchmarks? >>>> >>>> Less than 2 MB/s. >>>> >>>>> The server load just shows that the NFS requests are distributed over >>>>> your server threads. But that is not related to any CPU utilization. >>>> >>>> I know. NFS process never reaches 35% of one core. >>>> >>>> >>>> >>> As per Michael's email, re: isolating disk and client, can you isolate >>> which system it is slow serving to? I think that is important. >> >> Same result with Linux and FreeBSD. If I reduce number of nfs threads >> (currently 128), it seems to run better but I obtain on client side "nfs >> server not responding". >> >> Now, I only have two client (a Linux and a FreeBSD). FreeBSD is idle >> and I do some tests on Linux workstation. >> >> 1/ Linux rootfs is on a Raid1 disk on NetBSD server. >> 2/ iftop shows that nfs server is idle too (a few Kbps). >> 3/ apt update && apt dist-upgrade is very slow (-dev packages with a lot >> of little files). >> 4/ make -j1 kicad (9.0), sources on a Raid5 volume shows a nfs mean >> throughput around 40 Mbps. nfs process eats 1 to 2 % od server CPU. >> 5/ now, I start another compilation and load is rising on server side : >> >> load averages: 10.0, 3.17, 2.06; up 16+01:28:30 10:10:27 >> 93 processes: 92 sleeping, 1 on CPU >> CPU states: 0.1% user, 0.0% nice, 0.1% system, 0.0% interrupt, 99.7% idle >> Memory: 7838M Act, 3937M Inact, 49M Wired, 153M Exec, 9617M File, 84M >> Free >> Swap: 16G Total, 16G Free / Pools: 3708M Used / Network: 2647K In, >> 8700K Out >> >> PID USERNAME PRI NICE SIZE RES STATE TIME WCPU CPU >> COMMAND >> 4326 root 85 0 600M 8248K nfsd/4 823:01 7.13% 7.13% nfsd >> 2553 root 85 0 20M 2640K kqueue/3 2:59 4.88% 4.88% >> syslogd >> 0 root 221 0 0K 64M rfnode/3 803:17 4.10% 4.10% >> [system] >> 930 root 85 0 12M 1900K select/0 3:26 1.71% 1.71% >> rpc.lockd >> >> >> 6/ dd if=/dev/zero of=test.dd count=10 bs=100M >> nfs throughput rises until 850 Mbps (iftop) >> but load average on server side until 56 ! >> >> hilbert:[~] > dd if=/dev/zero of=test.dd count=10 bs=100M >> 10+0 enregistrements lus >> 10+0 enregistrements écrits >> 1048576000 octets (1,0 GB, 1000 MiB) copiés, 69,9613 s, 15,0 MB/s > > > If the load is going up but not CPU usage, perhaps something is blocking > a process? Lock contention? > > If you do a process list (PS) are there any processes in D state on the > server when you perform work over NFS? Only nfsd and kernel : legendre# ps auwx | grep ' D' root 23258 68.9 0.1 614028 8312 ? Dsl 12:14PM 0:36.32 /usr/sbin/nfsd -n 128 root 0 0.1 1.1 0 182868 ? DKl 12Feb26 807:12.02 [system] > I would, personally, also look at using ktruss on the NFS server PID. > Watch the output fly past but hope to see some form of contention. :-) > If seen, then output to a file for later viewing. I obtain a lot of : 23258 26255 nfsd stop kernel 23258 26255 nfsd resume kernel 23258 26255 nfsd stop kernel 23258 26255 nfsd resume kernel 23258 13228 nfsd stop kernel 23258 13228 nfsd resume kernel 23258 9705 nfsd stop kernel 23258 9705 nfsd resume kernel 23258 26255 nfsd stop kernel 23258 26255 nfsd resume kernel 23258 9696 nfsd stop kernel 23258 9696 nfsd resume kernel 23258 26255 nfsd stop kernel 23258 26255 nfsd resume kernel 23258 26255 nfsd stop kernel 23258 26255 nfsd resume kernel 23258 26255 nfsd stop kernel 23258 26255 nfsd resume kernel 23258 22577 nfsd stop kernel 23258 22577 nfsd resume kernel 23258 22577 nfsd stop kernel 23258 22577 nfsd resume kernel 23258 26255 nfsd stop kernel 23258 26255 nfsd resume kernel 23258 14759 nfsd stop kernel 23258 14759 nfsd resume kernel 23258 26255 nfsd stop kernel Regards, JB
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