Date: Fri, 11 Aug 2017 11:28:21 +0500 From: "Eugene M. Zheganin" <emz@norma.perm.ru> To: freebsd-fs@freebsd.org Cc: freebsd-stable <freebsd-stable@FreeBSD.org> Subject: zfs listing and CPU Message-ID: <aa26e888-05ef-c876-abf3-778ff08f4857@norma.perm.ru>
next in thread | raw e-mail | index | archive | help
Hi,
Why does the zfs listing eat so much of the CPU ?
last pid: 47151; load averages: 3.97, 6.35,
6.13 up 1+23:21:18 09:15:13
146 processes: 3 running, 142 sleeping, 1 waiting
CPU: 0.0% user, 0.0% nice, 30.5% system, 0.3% interrupt, 69.2% idle
Mem: 44M Active, 360M Inact, 37G Wired, 25G Free
ARC: 32G Total, 14G MFU, 17G MRU, 312M Anon, 803M Header, 523M Other
Swap: 32G Total, 185M Used, 32G Free
PID USERNAME THR PRI NICE SIZE RES STATE C TIME WCPU COMMAND
11 root 32 155 ki31 0K 512K CPU0 0 1104.1 2666.23%
idle
0 root 9880 -16 - 0K 154M swapin 11 314.0H 281.29%
kernel
13 root 3 -8 - 0K 48K gread 0 20.9H 28.71% geom
47114 root 1 20 0 40432K 3840K db->db 4 0:05 26.84% zfs
47099 root 1 20 0 40432K 3840K zio->i 17 0:05 26.83% zfs
47106 root 1 20 0 40432K 3840K db->db 21 0:05 26.81% zfs
47150 root 1 20 0 40432K 3428K db->db 13 0:03 26.31% zfs
47141 root 1 20 0 40432K 3428K zio->i 28 0:03 26.31% zfs
47135 root 1 20 0 40432K 3312K g_wait 9 0:03 25.51% zfs
4 root 7 -16 - 0K 112K - 20 975:01 19.73% cam
5 root 2494 -8 - 0K 39952K arc_re 18 20.2H 18.58%
zfskern
12 root 65 -60 - 0K 1040K WAIT 0 17.8H 15.64% intr
22 root 2 -16 - 0K 32K psleep 3 66:34 7.31%
pagedaemon
590 root 10 -16 - 0K 160K - 21 177:02 2.96% ctl
[...]
This is from winter 2017 11-STABLE (r310734), one of the 'zfs'es is
cloning, and all the others are 'zfs list -t all'. I have like 25 gigs
of free RAM, do I have any chance of speeding this up using may be some
caching or some sysctl tuning ? We are using a simple ZFS web API that
may issue concurrent or sequential listing requests, so as you can see
they sometimes do stack.
Thanks.
Eugene.
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?aa26e888-05ef-c876-abf3-778ff08f4857>