Date: Tue, 2 Jan 2018 12:13:44 -0800 From: Mark Millard <markmi@dsl-only.net> To: Allan Jude <allanjude@freebsd.org> Cc: FreeBSD Hackers <freebsd-hackers@freebsd.org> Subject: Re: rpi2 head -r327485 (e.g.): rpi2 leaves one "CPU n" always idle for some boots Message-ID: <85268695-3440-4B94-BF3D-68A38E204F50@dsl-only.net> In-Reply-To: <9da67685-d1c2-b6e0-cc32-efb49e67f0b1@freebsd.org> References: <3258F809-F179-4EB7-857C-74667BECD360@dsl-only.net> <9da67685-d1c2-b6e0-cc32-efb49e67f0b1@freebsd.org>
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On 2018-Jan-2, at 12:01 PM, Allan Jude <allanjude at freebsd.org> wrote:
> On 2018-01-02 14:48, Mark Millard 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
>>=20
>>=20
>> =3D=3D=3D
>> Mark Millard
>> markmi at dsl-only.net
>>=20
>> _______________________________________________
>> freebsd-hackers@freebsd.org mailing list
>> https://lists.freebsd.org/mailman/listinfo/freebsd-hackers
>> To unsubscribe, send any mail to =
"freebsd-hackers-unsubscribe@freebsd.org"
>>=20
>=20
> Have you tried using 'cpuset' to force each of the 4 to run on a
> specific CPU? What happens if you force it to run on cpu #2?
# cpuset -c -l 2 openssl speed 1>/dev/null 2>&1 &
results in:
last pid: 2120; load averages: 2.95, 2.44, 2.25 =
=
up 0+10:26:07 12:08:54
18 processes: 2 running, 16 sleeping
CPU 0: 0.0% user, 0.0% nice, 0.0% system, 4.7% interrupt, 95.3% idle
CPU 1: 0.4% user, 0.0% nice, 0.0% system, 0.0% interrupt, 99.6% idle
CPU 2: 0.0% user, 0.0% nice, 0.0% system, 0.0% interrupt, 100% idle
CPU 3: 0.0% user, 0.0% nice, 0.0% system, 0.0% interrupt, 100% idle
Mem: 1852K Active, 587M Inact, 5368K Laundry, 145M Wired, 86M Buf, 53M =
Free
Swap: 1536M Total, 1536M Free
PID USERNAME THR PRI NICE SIZE RES SWAP STATE C TIME =
CPU COMMAND
2120 root 1 20 0 6432K 2872K 0K CPU1 1 0:00 =
0.22% top -CawPopid
2118 root 1 29 0 7256K 4432K 0K RUN 1 0:00 =
0.00% openssl speed
. . .
With the other 3 also assigned:
last pid: 2138; load averages: 4.45, 3.04, 2.51 =
=
up 0+10:28:48 12:11:35
21 processes: 5 running, 16 sleeping
CPU 0: 93.7% user, 0.0% nice, 1.6% system, 4.7% interrupt, 0.0% idle
CPU 1: 100% user, 0.0% nice, 0.0% system, 0.0% 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: 3632K Active, 587M Inact, 5368K Laundry, 145M Wired, 86M Buf, 51M =
Free
Swap: 1536M Total, 1536M Free
PID USERNAME THR PRI NICE SIZE RES SWAP STATE C TIME =
CPU COMMAND
2138 root 1 20 0 6472K 2888K 0K CPU1 1 0:00 =
0.24% top -CawPopid
2137 root 1 100 0 7256K 4436K 0K CPU3 3 0:25 =
96.79% openssl speed
2124 root 1 102 0 7256K 4436K 0K RUN 1 0:37 =
101.66% openssl speed
2123 root 1 101 0 7256K 4436K 0K CPU0 0 0:44 =
95.07% openssl speed
2118 root 1 29 0 7256K 4432K 0K RUN 1 0:00 =
0.00% openssl speed
. . .
Thus the difference is that the one instance
of openssl speed does not run at all.
=3D=3D=3D
Mark Millard
markmi at dsl-only.net
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