Date: Tue, 2 Jan 2018 11:59:11 -0800 From: Mark Millard <markmi@dsl-only.net> To: Freebsd-arm <freebsd-arm@freebsd.org>, FreeBSD Hackers <freebsd-hackers@freebsd.org>, FreeBSD Current <freebsd-current@freebsd.org> Subject: Re: rpi2 head -r327485 (e.g.): rpi2 leaves one "CPU n" always idle for some boots Message-ID: <422E2742-7170-4D1A-894F-F310EE819E3A@dsl-only.net> In-Reply-To: <3258F809-F179-4EB7-857C-74667BECD360@dsl-only.net> References: <3258F809-F179-4EB7-857C-74667BECD360@dsl-only.net>
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On 2018-Jan-2, at 11:48 AM, Mark Millard <markmi at dsl-only.net> wrote:
> I've seen this over many versions of head for months
> but have never managed to find a way to force it to
> happen. It just shows up once and a while.
>=20
> Thus, I'm just dumping out some top and kernel information
> here for reference. I've used:
>=20
> openssl speed 1>/dev/null 2>&1 &
> openssl speed 1>/dev/null 2>&1 &
> openssl speed 1>/dev/null 2>&1 &
> openssl speed 1>/dev/null 2>&1 &
>=20
> to give the rpi2 4 active processes. Various outputs
> are from different times without a reboot between.
>=20
> top -CaePores shows the likes of:
>=20
> PID USERNAME THR PRI NICE SIZE RES SWAP STATE C TIME =
CPU COMMAND
> 614 root 1 20 0 10452K 10480K 0K select 1 0:00 =
0.03% /usr/sbin/ntpd -g -c /etc/ntp.conf -p /var/run/ntpd.pid -f =
/var/db/ntpd.drift
> 661 root 1 52 0 9984K 6132K 0K select 1 0:00 =
0.00% /usr/sbin/sshd
> 751 root 1 101 0 7256K 4276K 0K RUN 1 0:28 =
99.57% openssl speed
> 750 root 1 100 0 7256K 4276K 0K CPU0 0 0:32 =
94.83% openssl speed
> 753 root 1 86 0 7256K 4276K 0K RUN 3 0:13 =
52.36% openssl speed
> 752 root 1 86 0 7256K 4276K 0K CPU3 3 0:14 =
46.54% openssl speed
> 363 root 1 20 0 6428K 3840K 0K select 3 0:00 =
0.00% /sbin/devd
> . . .
>=20
> and:
>=20
> last pid: 754; load averages: 3.70, 2.38, 1.58 =
=
up 0+00:16:50 01:59:37
> 21 processes: 5 running, 16 sleeping
> CPU 0: 94.9% user, 0.0% nice, 0.0% system, 5.1% interrupt, 0.0% =
idle
> CPU 1: 99.6% user, 0.0% nice, 0.0% system, 0.4% interrupt, 0.0% =
idle
> CPU 2: 0.0% user, 0.0% nice, 0.0% system, 0.0% interrupt, 100% =
idle
> CPU 3: 100% user, 0.0% nice, 0.0% system, 0.0% interrupt, 0.0% =
idle
> Mem: 12M Active, 1136K Inact, 56M Wired, 30M Buf, 722M Free
> Swap: 1536M Total, 6M Free
>=20
> =46rom problem boot to problem boot, the CPU that stays
> idle has varied but usually has been CPU 2. I've never
> seen 2 or more stuck in idle.
>=20
> show allpcpu shows the likes of:
>=20
> db> show allpcpu
> Current CPU: 0
>=20
> cpuid =3D 0
> dynamic pcpu =3D 0x3d2540
> curthread =3D 0xd8478ae0: pid 2032 tid 100150 "openssl"
> curpcb =3D 0xd852ae98
> fpcurthread =3D 0xd8478ae0: pid 2032 "openssl"
> idlethread =3D 0xc376fae0: tid 100002 "idle: cpu0"
> curpmap =3D 0xd8e43bf4
> curvnet =3D 0
>=20
> cpuid =3D 1
> dynamic pcpu =3D 0x3998540
> curthread =3D 0xd7e5b3a0: pid 2031 tid 100173 "openssl"
> curpcb =3D 0xda7e0e98
> fpcurthread =3D 0xd7e5b3a0: pid 2031 "openssl"
> idlethread =3D 0xc376f740: tid 100003 "idle: cpu1"
> curpmap =3D 0xd8e43ec4
> curvnet =3D 0
>=20
> cpuid =3D 2
> dynamic pcpu =3D 0x3999540
> curthread =3D 0xc376f3a0: pid 10 tid 100004 "idle: cpu2"
> curpcb =3D 0xc378ae98
> fpcurthread =3D none
> idlethread =3D 0xc376f3a0: tid 100004 "idle: cpu2"
> curpmap =3D 0
> curvnet =3D 0
>=20
> cpuid =3D 3
> dynamic pcpu =3D 0x399a540
> curthread =3D 0xd8477000: pid 2034 tid 100167 "openssl"
> curpcb =3D 0xd876de98
> fpcurthread =3D 0xd8477000: pid 2034 "openssl"
> idlethread =3D 0xc376f000: tid 100005 "idle: cpu3"
> curpmap =3D 0xc377ab04
> curvnet =3D 0
>=20
> In other words: it appears that the cpuN (here cpu2) is
> left with idle scheduled all the time for some reason.
>=20
> ps from db> shows things like:
>=20
>=20
> db> ps
> pid ppid pgrp uid state wmesg wchan cmd
> 2034 714 2034 0 R+ openssl
> 2033 714 2033 0 R+ CPU 3 openssl
> 2032 714 2032 0 R+ CPU 0 openssl
> 2031 714 2031 0 R+ CPU 1 openssl
>=20
> (then later:)
>=20
> db> ps
> pid ppid pgrp uid state wmesg wchan cmd
> 2034 714 2034 0 R+ CPU 3 openssl
> 2033 714 2033 0 R+ openssl
> 2032 714 2032 0 R+ CPU 0 openssl
> 2031 714 2031 0 R+ CPU 1 openssl
>=20
> There is also:
>=20
> 10 0 0 0 RL (threaded) [idle]
> 100002 CanRun [idle: cpu0]
> 100003 CanRun [idle: cpu1]
> 100004 CanRun [idle: cpu2]
> 100005 CanRun [idle: cpu3]
>=20
>=20
> These are from:
>=20
> # uname -apKU
> FreeBSD rpi2 12.0-CURRENT FreeBSD 12.0-CURRENT r327485M arm armv7 =
1200054 1200054
I probably should have reported that as I remember the
following sort of thing is true for the problem
cpuN (here cpu2):
100074 D - 0xd6f5be80 [softirq_0]
100075 D - 0xd6f5be00 [softirq_1]
100076 RunQ [softirq_2]
100077 D - 0xd6f5bd00 [softirq_3]
100078 D - 0xd6f5bc80 [if_io_tqg_0]
100079 D - 0xd6f5bc00 [if_io_tqg_1]
100080 RunQ [if_io_tqg_2]
100081 D - 0xd6f5bb00 [if_io_tqg_3]
=3D=3D=3D
Mark Millard
markmi at dsl-only.net
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