From: cliff chen <1879425@bugs.launchpad.net>
To: qemu-devel@nongnu.org
Subject: [Bug 1879425] [NEW] The thread of "CPU 0 /KVM" keeping 99.9%CPU
Date: Tue, 19 May 2020 01:32:56 -0000 [thread overview]
Message-ID: <158985197617.30924.14122012304587735670.malonedeb@chaenomeles.canonical.com> (raw)
Public bug reported:
Hi Expert:
The VM is hung here after (2, or 3, or 5 and the longest time is 10 hours) by qemu-kvm.
Notes:
for VM:
OS: RHEL 7.6
CPU: 1
MEM:4G
For qemu-kvm:
1) version:
/usr/libexec/qemu-kvm -version
QEMU emulator version 2.10.0(qemu-kvm-ev-2.10.0-21.el7_5.4.1)
2) once the issue is occurred, the CPU of "CPU0 /KVM" is more than 99% by com "top -p VM_pro_ID"
PID UDER PR NI RES S % CPU %MEM TIME+ COMMAND
872067 qemu 20 0 1.6g R 99.9 0.6 37:08.87 CPU 0/KVM
3) use "pstack 493307" and below is function trace
Thread 1 (Thread 0x7f2572e73040 (LWP 872067)):
#0 0x00007f256cad8fcf in ppoll () from /lib64/libc.so.6
#1 0x000055ff34bdf4a9 in qemu_poll_ns ()
#2 0x000055ff34be02a8 in main_loop_wait ()
#3 0x000055ff348bfb1a in main ()
4) use strace "strace -tt -ff -p 872067 -o cfx" and below log keep printing
21:24:02.977833 ppoll([{fd=4, events=POLLIN}, {fd=6, events=POLLIN}, {fd=8, events=POLLIN}, {fd=9, events=POLLIN}, {fd=80, events=POLLIN}, {fd=82, events=POLLIN}, {fd=84, events=POLLIN}, {fd=115, events=POLLIN}, {fd=121, events=POLLIN}], 9, {0, 0}, NULL, 8) = 0 (Timeout)
21:24:02.977918 ppoll([{fd=4, events=POLLIN}, {fd=6, events=POLLIN}, {fd=8, events=POLLIN}, {fd=9, events=POLLIN}, {fd=80, events=POLLIN}, {fd=82, events=POLLIN}, {fd=84, events=POLLIN}, {fd=115, events=POLLIN}, {fd=121, events=POLLIN}], 9, {0, 911447}, NULL, 8) = 0 (Timeout)
21:24:02.978945 ppoll([{fd=4, events=POLLIN}, {fd=6, events=POLLIN}, {fd=8, events=POLLIN}, {fd=9, events=POLLIN}, {fd=80, events=POLLIN}, {fd=82, events=POLLIN}, {fd=84, events=POLLIN}, {fd=115, events=POLLIN}, {fd=121, events=POLLIN}], 9, {0, 0}, NULL, 8) = 0 (Timeout)
Therefore, I think the thread "CPU 0/KVM" is in tight loop.
5) use reset can recover this issue. however, it will reoccurred again.
Current work around is increase one CPU for this VM, then issue is gone.
thanks
Cliff
** Affects: qemu
Importance: Undecided
Status: New
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https://bugs.launchpad.net/bugs/1879425
Title:
The thread of "CPU 0 /KVM" keeping 99.9%CPU
Status in QEMU:
New
Bug description:
Hi Expert:
The VM is hung here after (2, or 3, or 5 and the longest time is 10 hours) by qemu-kvm.
Notes:
for VM:
OS: RHEL 7.6
CPU: 1
MEM:4G
For qemu-kvm:
1) version:
/usr/libexec/qemu-kvm -version
QEMU emulator version 2.10.0(qemu-kvm-ev-2.10.0-21.el7_5.4.1)
2) once the issue is occurred, the CPU of "CPU0 /KVM" is more than 99% by com "top -p VM_pro_ID"
PID UDER PR NI RES S % CPU %MEM TIME+ COMMAND
872067 qemu 20 0 1.6g R 99.9 0.6 37:08.87 CPU 0/KVM
3) use "pstack 493307" and below is function trace
Thread 1 (Thread 0x7f2572e73040 (LWP 872067)):
#0 0x00007f256cad8fcf in ppoll () from /lib64/libc.so.6
#1 0x000055ff34bdf4a9 in qemu_poll_ns ()
#2 0x000055ff34be02a8 in main_loop_wait ()
#3 0x000055ff348bfb1a in main ()
4) use strace "strace -tt -ff -p 872067 -o cfx" and below log keep printing
21:24:02.977833 ppoll([{fd=4, events=POLLIN}, {fd=6, events=POLLIN}, {fd=8, events=POLLIN}, {fd=9, events=POLLIN}, {fd=80, events=POLLIN}, {fd=82, events=POLLIN}, {fd=84, events=POLLIN}, {fd=115, events=POLLIN}, {fd=121, events=POLLIN}], 9, {0, 0}, NULL, 8) = 0 (Timeout)
21:24:02.977918 ppoll([{fd=4, events=POLLIN}, {fd=6, events=POLLIN}, {fd=8, events=POLLIN}, {fd=9, events=POLLIN}, {fd=80, events=POLLIN}, {fd=82, events=POLLIN}, {fd=84, events=POLLIN}, {fd=115, events=POLLIN}, {fd=121, events=POLLIN}], 9, {0, 911447}, NULL, 8) = 0 (Timeout)
21:24:02.978945 ppoll([{fd=4, events=POLLIN}, {fd=6, events=POLLIN}, {fd=8, events=POLLIN}, {fd=9, events=POLLIN}, {fd=80, events=POLLIN}, {fd=82, events=POLLIN}, {fd=84, events=POLLIN}, {fd=115, events=POLLIN}, {fd=121, events=POLLIN}], 9, {0, 0}, NULL, 8) = 0 (Timeout)
Therefore, I think the thread "CPU 0/KVM" is in tight loop.
5) use reset can recover this issue. however, it will reoccurred again.
Current work around is increase one CPU for this VM, then issue is gone.
thanks
Cliff
To manage notifications about this bug go to:
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next reply other threads:[~2020-05-19 1:41 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-19 1:32 cliff chen [this message]
2020-05-20 1:41 ` [Bug 1879425] Re: The thread of "CPU 0 /KVM" keeping 99.9%CPU cliff chen
2020-05-20 7:23 ` cliff chen
2020-05-22 1:42 ` cliff chen
2020-05-22 5:10 ` Thomas Huth
2020-05-22 5:22 ` cliff chen
2020-05-22 6:02 ` Thomas Huth
2020-05-22 6:15 ` cliff chen
2020-05-25 2:29 ` cliff chen
2021-04-22 17:31 ` Thomas Huth
2021-04-23 4:17 ` Launchpad Bug Tracker
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