From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:54366) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RzYhr-0003hu-0b for qemu-devel@nongnu.org; Mon, 20 Feb 2012 14:15:31 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1RzYhm-0005Ai-N2 for qemu-devel@nongnu.org; Mon, 20 Feb 2012 14:15:26 -0500 Received: from ssl.dlh.net ([91.198.192.8]:37653) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RzYhm-0005Ab-9n for qemu-devel@nongnu.org; Mon, 20 Feb 2012 14:15:22 -0500 Message-ID: <4F429BC3.9000909@dlh.net> Date: Mon, 20 Feb 2012 20:15:15 +0100 From: Peter Lieven MIME-Version: 1.0 References: <4F428E53.2010602@dlh.net> <20120220184008.GF29601@redhat.com> In-Reply-To: <20120220184008.GF29601@redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] win7 bad i/o performance, high insn_emulation and exists List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Gleb Natapov Cc: qemu-devel@nongnu.org, kvm@vger.kernel.org On 20.02.2012 19:40, Gleb Natapov wrote: > On Mon, Feb 20, 2012 at 07:17:55PM +0100, Peter Lieven wrote: >> Hi, >> >> I came a across an issue with a Windows 7 (32-bit) as well as with a >> Windows 2008 R2 (64-bit) guest. >> >> If I transfer a file from the VM via CIFS or FTP to a remote machine, >> i get very poor read performance (around 13MB/s). The VM peaks at 100% >> cpu and I see a lot of insn_emulations and all kinds of exists in kvm_stat >> >> efer_reload 0 0 >> exits 2260976 79620 >> fpu_reload 6197 11 >> halt_exits 114734 5011 >> halt_wakeup 111195 4876 >> host_state_reload 1499659 60962 >> hypercalls 0 0 >> insn_emulation 1577325 58488 >> insn_emulation_fail 0 0 >> invlpg 0 0 >> io_exits 943949 40249 > Hmm, too many of those. > >> irq_exits 108679 5434 >> irq_injections 236545 10788 >> irq_window 7606 246 >> largepages 672 5 >> mmio_exits 460020 16082 >> mmu_cache_miss 119 0 >> mmu_flooded 0 0 >> mmu_pde_zapped 0 0 >> mmu_pte_updated 0 0 >> mmu_pte_write 13474 9 >> mmu_recycled 0 0 >> mmu_shadow_zapped 141 0 >> mmu_unsync 0 0 >> nmi_injections 0 0 >> nmi_window 0 0 >> pf_fixed 22803 35 >> pf_guest 0 0 >> remote_tlb_flush 239 2 >> request_irq 0 0 >> signal_exits 0 0 >> tlb_flush 20933 0 >> >> If I run the same VM with a Ubuntu 10.04.4 guest I get around 60MB/s >> throughput. The kvm_stats look a lot more sane. >> >> efer_reload 0 0 >> exits 6132004 17931 >> fpu_reload 19863 3 >> halt_exits 264961 3083 >> halt_wakeup 236468 2959 >> host_state_reload 1104468 3104 >> hypercalls 0 0 >> insn_emulation 1417443 7518 >> insn_emulation_fail 0 0 >> invlpg 0 0 >> io_exits 869380 2795 >> irq_exits 253501 2362 >> irq_injections 616967 6804 >> irq_window 201186 2161 >> largepages 1019 0 >> mmio_exits 205268 0 >> mmu_cache_miss 192 0 >> mmu_flooded 0 0 >> mmu_pde_zapped 0 0 >> mmu_pte_updated 0 0 >> mmu_pte_write 7440546 0 >> mmu_recycled 0 0 >> mmu_shadow_zapped 259 0 >> mmu_unsync 0 0 >> nmi_injections 0 0 >> nmi_window 0 0 >> pf_fixed 38529 30 >> pf_guest 0 0 >> remote_tlb_flush 761 1 >> request_irq 0 0 >> signal_exits 0 0 >> tlb_flush 0 0 >> >> I use virtio-net (with vhost-net) and virtio-blk. I tried disabling >> hpet (which basically illiminated the mmio_exits, but does not >> increase >> performance) and also commit (39a7a362e16bb27e98738d63f24d1ab5811e26a8 >> ) - no improvement. >> >> My commandline: >> /usr/bin/qemu-kvm-1.0 -netdev >> type=tap,id=guest8,script=no,downscript=no,ifname=tap0,vhost=on >> -device virtio-net-pci,netdev=guest8,mac=52:54:00:ff:00:d3 -drive format=host_device,file=/dev/mapper/iqn.2001-05.com.equallogic:0-8a0906-eeef4e007-a8a9f3818674f2fc-lieven-windows7-vc-r80788,if=virtio,cache=none,aio=native >> -m 2048 -smp 2 -monitor tcp:0:4001,server,nowait -vnc :1 -name >> lieven-win7-vc -boot order=dc,menu=off -k de -pidfile >> /var/run/qemu/vm-187.pid -mem-path /hugepages -mem-prealloc -cpu >> host -rtc base=localtime -vga std -usb -usbdevice tablet -no-hpet >> >> What further information is needed to debug this further? >> > Which kernel version (looks like something recent)? 2.6.38 with kvm-kmod 3.2 > Which host CPU (looks like something old)? why? i guess its (quite) new. vendor_id : GenuineIntel cpu family : 6 model : 44 model name : Intel(R) Xeon(R) CPU L5640 @ 2.27GHz stepping : 2 cpu MHz : 1596.000 cache size : 12288 KB physical id : 1 siblings : 6 core id : 10 cpu cores : 6 apicid : 52 initial apicid : 52 fpu : yes fpu_exception : yes cpuid level : 11 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx pdpe1gb rdtscp lm constant_tsc arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc aperfmperf pni pclmulqdq dtes64 monitor ds_cpl vmx smx est tm2 ssse3 cx16 xtpr pdcm dca sse4_1 sse4_2 popcnt aes lahf_lm arat dts tpr_shadow vnmi flexpriority ept vpid bogomips : 2254.43 clflush size : 64 cache_alignment : 64 address sizes : 40 bits physical, 48 bits virtual > Which Windows' virtio drivers are you using? i used to use 0.1-16 and today also tried 0.1-22 from http://alt.fedoraproject.org/pub/alt/virtio-win/latest/images/ > Take a trace like described here http://www.linux-kvm.org/page/Tracing > (with -no-hpet please). will prepare this. > Try to use -cpu host,+x2apic. It may help Linux guest performance. Thanks, it improved throughput a little while lowering the cpu usage. Windows does not support this? Thanks Peter > -- > Gleb.