Hi all, I'm using qemu to start vm in huge page enviroment, I use CMD1 and CMD2 to test the time of start of a vm, CMD1 contains option '-mem-prealloc', CMD2 does not contain this.
I found while using CMD1, the time to run this command is longer then CMD2. For words, I know this option is to wait memory ready, but for code, I don't know where is the different with CMD1 and CMD2. As I print log of CMD1 and CMD2, I found for CMD1, there are about 10 second to print first log. I don't know for '-mem-prealloc' option, what qemu wait for? thank you~ detail of test: CMD1="$QEMU_CMD -D qemu.log -trace events=qemu-events-all -enable-kvm -cpu qemu64,+vmx,+ssse3,+sse4.1,+sse4.2,+x2apic,+aes,+avx,+vme,+pat,+ss,+pclmulqdq,+xsave,level=13 -machine pc,accel=kvm -chardev socket,id=hmqmondev,port=55908,host=127.0.0.1,nodelay,server,nowait -mon chardev=hmqmondev,id=hmqmon,mode=readline -rtc base=utc,clock=host,driftfix=none -usb -device usb-tablet -daemonize -nodefaults -nodefconfig -no-kvm-pit-reinjection -global kvm-pit.lost_tick_policy=discard -vga std -k en-us -smp 8 -name gangyewei-qemutime-1 -m 40960 -boot order=cdn -vnc :8,password -drive file=$DISK_0,if=none,id=drive_0,format=qcow2,cache=none,aio=native -device virtio-blk-pci,id=dev_drive_0,drive=drive_0,bus=pci.0,addr=0x5 -drive file=$DISK_1,if=none,id=drive_1,format=qcow2,cache=none,aio=native -device virtio-blk-pci,id=dev_drive_1,drive=drive_1,bus=pci.0,addr=0x6 -drive file=$DISK_2,if=none,id=drive_2,format=qcow2,cache=none,aio=native -device virtio-blk-pci,id=dev_drive_2,drive=drive_2,bus=pci.0,addr=0x7 -device ide-cd,drive=ide0-cd0,bus=ide.1,unit=1 -drive id=ide0-cd0,media=cdrom,if=none -chardev socket,id=char-n-52b49b80,path=/usr/local/var/run/openvswitch/n-52b49b80,server -netdev type=vhost-user,id=n-52b49b80,chardev=char-n-52b49b80,vhostforce=on -device virtio-net-pci,netdev=n-52b49b80,mac=00:22:52:b4:9b:80,id=netdev-n-52b49b80,addr=0xf$(nic_speed 10000) -object memory-backend-file,id=mem,size=40960M,mem-path=/mnt/huge,share=on -numa node,memdev=mem -pidfile $PID_FILE -chardev socket,path=/opt/cloud/workspace/servers/4511f52a-f450-40d3-9417-a1e0a27ed507/qga.sock,server,nowait,id=qga0 -device virtio-serial -device virtserialport,chardev=qga0,name=org.qemu.guest_agent.0" CMD2="$QEMU_CMD -D qemu.log -trace events=qemu-events-all -enable-kvm -cpu qemu64,+vmx,+ssse3,+sse4.1,+sse4.2,+x2apic,+aes,+avx,+vme,+pat,+ss,+pclmulqdq,+xsave,level=13 -machine pc,accel=kvm -chardev socket,id=hmqmondev,port=55908,host=127.0.0.1,nodelay,server,nowait -mon chardev=hmqmondev,id=hmqmon,mode=readline -rtc base=utc,clock=host,driftfix=none -usb -device usb-tablet -daemonize -nodefaults -nodefconfig -no-kvm-pit-reinjection -global kvm-pit.lost_tick_policy=discard -vga std -k en-us -smp 8 -name gangyewei-qemutime-1 -m 40960 -boot order=cdn -vnc :8,password -drive file=$DISK_0,if=none,id=drive_0,format=qcow2,cache=none,aio=native -device virtio-blk-pci,id=dev_drive_0,drive=drive_0,bus=pci.0,addr=0x5 -drive file=$DISK_1,if=none,id=drive_1,format=qcow2,cache=none,aio=native -device virtio-blk-pci,id=dev_drive_1,drive=drive_1,bus=pci.0,addr=0x6 -drive file=$DISK_2,if=none,id=drive_2,format=qcow2,cache=none,aio=native -device virtio-blk-pci,id=dev_drive_2,drive=drive_2,bus=pci.0,addr=0x7 -device ide-cd,drive=ide0-cd0,bus=ide.1,unit=1 -drive id=ide0-cd0,media=cdrom,if=none -chardev socket,id=char-n-52b49b80,path=/usr/local/var/run/openvswitch/n-52b49b80,server -netdev type=vhost-user,id=n-52b49b80,chardev=char-n-52b49b80,vhostforce=on -device virtio-net-pci,netdev=n-52b49b80,mac=00:22:52:b4:9b:80,id=netdev-n-52b49b80,addr=0xf$(nic_speed 10000) -object memory-backend-file,id=mem,size=40960M,mem-path=/mnt/huge,share=on -numa node,memdev=mem -mem-prealloc -pidfile $PID_FILE -chardev socket,path=/opt/cloud/workspace/servers/4511f52a-f450-40d3-9417-a1e0a27ed507/qga.sock,server,nowait,id=qga0 -device virtio-serial -device virtserialport,chardev=qga0,name=org.qemu.guest_agent.0" time to run CMD1: [root@yf-mos-test-net14 4511f52a-f450-40d3-9417-a1e0a27ed507]# sh startvm ls: cannot access /opt/cloud/workspace/servers/4511f52a-f450-40d3-9417-a1e0a27ed507/STATEFILE*: No such file or directory Wed Oct 25 16:52:51 CST 2017 (unix time is 1508921571) qemu-system-x86_64_2.6.0:qemu-events-all:1045: WARNING: trace event 'qxl_interface_set_mm_time' is not traceable qemu-system-x86_64_2.6.0:qemu-events-all:1046: WARNING: trace event 'qxl_io_write_vga' is not traceable qemu-system-x86_64_2.6.0:qemu-events-all:1318: WARNING: trace event 'exec_tb' is not traceable qemu-system-x86_64_2.6.0:qemu-events-all:1319: WARNING: trace event 'exec_tb_nocache' is not traceable qemu-system-x86_64_2.6.0:qemu-events-all:1320: WARNING: trace event 'exec_tb_exit' is not traceable qemu-system-x86_64_2.6.0: -no-kvm-pit-reinjection: warning: deprecated, replaced by -global kvm-pit.lost_tick_policy=discard Wed Oct 25 16:53:02 CST 2017 (unix time is 1508921582) qemu started first log of CMD1: 45704@1508921581.767831:qio_channel_socket_new Socket new ioc=0x55555640efd0 I don't know why first log happends in 1508921581, not the start up time, which is 1508921571. time to run CMD2: [root@yf-mos-test-net14 4511f52a-f450-40d3-9417-a1e0a27ed507]# sh startvm ls: cannot access /opt/cloud/workspace/servers/4511f52a-f450-40d3-9417-a1e0a27ed507/STATEFILE*: No such file or directory Wed Oct 25 18:15:35 CST 2017 qemu-system-x86_64_2.6.0:qemu-events-all:1045: WARNING: trace event 'qxl_interface_set_mm_time' is not traceable qemu-system-x86_64_2.6.0:qemu-events-all:1046: WARNING: trace event 'qxl_io_write_vga' is not traceable qemu-system-x86_64_2.6.0:qemu-events-all:1318: WARNING: trace event 'exec_tb' is not traceable qemu-system-x86_64_2.6.0:qemu-events-all:1319: WARNING: trace event 'exec_tb_nocache' is not traceable qemu-system-x86_64_2.6.0:qemu-events-all:1320: WARNING: trace event 'exec_tb_exit' is not traceable qemu-system-x86_64_2.6.0: -no-kvm-pit-reinjection: warning: deprecated, replaced by -global kvm-pit.lost_tick_policy=discard Wed Oct 25 18:15:36 CST 2017 qemu started first log of CMD1: 45167@1508926535.502360:qio_channel_socket_new Socket new ioc=0x55555640efd0
