Re: [kvm-devel] High vm-exit latencies during kvm boot-up/shutdown

Avi Kivity wrote: > Dong, Eddie wrote: >> Jan Kiszka wrote: >> >>> So if you want the higher performance of PCIe you need >>> performance-killing wbindv (not to speak of latency)? That sounds a >>> bit contradictory to me. So this is also true for native PCIe usage? >>> >>> >> >> Mmm, I won't s

Re: [kvm-devel] High vm-exit latencies during kvm boot-up/shutdown

Dong, Eddie wrote: > Jan Kiszka wrote: > >> So if you want the higher performance of PCIe you need >> performance-killing wbindv (not to speak of latency)? That sounds a >> bit contradictory to me. So this is also true for native PCIe usage? >> >> > > Mmm, I won't say so. When you want to g

Re: [kvm-devel] High vm-exit latencies during kvm boot-up/shutdown

Dong, Eddie wrote: >>> >> Okay. In that case the host can emulate wbinvd by using the clflush >> instruction, which is much faster (although overall execution time may >> be higher), maintaining real-time response times. >> > > Faster? maybe. > The issue is clflush take va parameter. S

Re: [kvm-devel] High vm-exit latencies during kvm boot-up/shutdown

Avi Kivity wrote: > Dong, Eddie wrote: >> Avi Kivity wrote: >> >>> Dong, Eddie wrote: >>> > There's a two-liner required to make it work. I'll add it soon. > > > But you still needs to issue WBINVD to all pCPUs which just move non-response time from one place to anot

Re: [kvm-devel] High vm-exit latencies during kvm boot-up/shutdown

Dong, Eddie wrote: > > Jan Kiszka wrote: > > > > So if you want the higher performance of PCIe you need > > performance-killing wbindv (not to speak of latency)? That sounds a > > bit contradictory to me. So this is also true for native PCIe usage? > > > > Mmm, I won't say so. When you want to get

Re: [kvm-devel] High vm-exit latencies during kvm boot-up/shutdown

Dong, Eddie wrote: > Avi Kivity wrote: >> Dong, Eddie wrote: There's a two-liner required to make it work. I'll add it soon. >>> But you still needs to issue WBINVD to all pCPUs which just move >>> non-response time from one place to another, not? >>> >> You don't actually need to e

Re: [kvm-devel] High vm-exit latencies during kvm boot-up/shutdown

Jan Kiszka wrote: > Dong, Eddie wrote: > >> Avi Kivity wrote: >> >>> Dong, Eddie wrote: >>> > There's a two-liner required to make it work. I'll add it soon. > > > But you still needs to issue WBINVD to all pCPUs which just move non-response time

Re: [kvm-devel] High vm-exit latencies during kvm boot-up/shutdown

Dong, Eddie wrote: > Avi Kivity wrote: > >> Dong, Eddie wrote: >> There's a two-liner required to make it work. I'll add it soon. >>> But you still needs to issue WBINVD to all pCPUs which just move >>> non-response time from one place to another, not? >>> >>>

Re: [kvm-devel] High vm-exit latencies during kvm boot-up/shutdown

Jan Kiszka wrote: > > So if you want the higher performance of PCIe you need > performance-killing wbindv (not to speak of latency)? That sounds a > bit contradictory to me. So this is also true for native PCIe usage? > Mmm, I won't say so. When you want to get RT performance, you won't use unkn

Re: [kvm-devel] High vm-exit latencies during kvm boot-up/shutdown

Avi Kivity wrote: > Dong, Eddie wrote: >>> There's a two-liner required to make it work. I'll add it soon. >>> >>> >> But you still needs to issue WBINVD to all pCPUs which just move >> non-response time from one place to another, not? >> > > You don't actually need to emulate wbinvd, you can

Re: [kvm-devel] High vm-exit latencies during kvm boot-up/shutdown

Dong, Eddie wrote: >> There's a two-liner required to make it work. I'll add it soon. >> >> > But you still needs to issue WBINVD to all pCPUs which just move > non-response time from one place to another, not? > You don't actually need to emulate wbinvd, you can just ignore it. The onl

Re: [kvm-devel] High vm-exit latencies during kvm boot-up/shutdown

> > There's a two-liner required to make it work. I'll add it soon. > But you still needs to issue WBINVD to all pCPUs which just move non-response time from one place to another, not? Eddie - This SF.net email is sponsore

Re: [kvm-devel] High vm-exit latencies during kvm boot-up/shutdown

Jan Kiszka wrote: > Avi Kivity wrote: > >> Jan Kiszka wrote: >> >>> Got it! It's wbinvd from smm_init in rombios32.c! Anyone any comments on >>> this? >>> >>> >> Ha! A real life 300usec instruction! >> >> Unfortunately, it cannot be trapped on Intel (it can be trapped on >> AMD)

Re: [kvm-devel] High vm-exit latencies during kvm boot-up/shutdown

Avi Kivity wrote: > Jan Kiszka wrote: >> Got it! It's wbinvd from smm_init in rombios32.c! Anyone any comments on >> this? >> > > Ha! A real life 300usec instruction! > > Unfortunately, it cannot be trapped on Intel (it can be trapped on > AMD). Looks like a minor hole in VT, as a guest can

Re: [kvm-devel] High vm-exit latencies during kvm boot-up/shutdown

Jan Kiszka wrote: > Avi Kivity wrote: > >> Jan Kiszka wrote: >> >>> Avi Kivity wrote: >>> >>> Jan Kiszka wrote: > I ran > > user/kvmctl user/test/bootstrap user/test/smp.flat > > with the busy loop hacked into bootstrap, but I got n

Re: [kvm-devel] High vm-exit latencies during kvm boot-up/shutdown

Avi Kivity wrote: > Jan Kiszka wrote: >> Avi Kivity wrote: >> >>> Jan Kiszka wrote: >>> I ran user/kvmctl user/test/bootstrap user/test/smp.flat with the busy loop hacked into bootstrap, but I got no latency spots this time. And what should I look for in the ou

Re: [kvm-devel] High vm-exit latencies during kvm boot-up/shutdown

Jan Kiszka wrote: > Avi Kivity wrote: > >> Jan Kiszka wrote: >> >>> I ran >>> >>> user/kvmctl user/test/bootstrap user/test/smp.flat >>> >>> with the busy loop hacked into bootstrap, but I got no latency spots >>> this time. And what should I look for in the output of kvm_stat? >>> >>> >

Re: [kvm-devel] High vm-exit latencies during kvm boot-up/shutdown

Avi Kivity wrote: > Jan Kiszka wrote: >> I ran >> >> user/kvmctl user/test/bootstrap user/test/smp.flat >> >> with the busy loop hacked into bootstrap, but I got no latency spots >> this time. And what should I look for in the output of kvm_stat? >> >> > > The first numeric column is the total

Re: [kvm-devel] High vm-exit latencies during kvm boot-up/shutdown

Jan Kiszka wrote: > I ran > > user/kvmctl user/test/bootstrap user/test/smp.flat > > with the busy loop hacked into bootstrap, but I got no latency spots > this time. And what should I look for in the output of kvm_stat? > > The first numeric column is the total number of exits; the second is t

Re: [kvm-devel] High vm-exit latencies during kvm boot-up/shutdown

Avi Kivity wrote: > Jan Kiszka wrote: >> Avi Kivity wrote: >> >>> Jan Kiszka wrote: >>> It's both: -rt tests were performed with nosmp (-rt locks up under SMP here), and the Xenomai tests, including the last instrumentation, ran in SMP mode. So I tend to exclude SMP effects.

Re: [kvm-devel] High vm-exit latencies during kvm boot-up/shutdown

Jan Kiszka wrote: > Avi Kivity wrote: > >> Jan Kiszka wrote: >> >>> It's both: -rt tests were performed with nosmp (-rt locks up under SMP >>> here), and the Xenomai tests, including the last instrumentation, ran in >>> SMP mode. So I tend to exclude SMP effects. >>> >>> Do you have some su

Re: [kvm-devel] High vm-exit latencies during kvm boot-up/shutdown

Avi Kivity wrote: > Jan Kiszka wrote: >> It's both: -rt tests were performed with nosmp (-rt locks up under SMP >> here), and the Xenomai tests, including the last instrumentation, ran in >> SMP mode. So I tend to exclude SMP effects. >> >> Do you have some suggestion how to analyse what the guest

Re: [kvm-devel] High vm-exit latencies during kvm boot-up/shutdown

Jan Kiszka wrote: > It's both: -rt tests were performed with nosmp (-rt locks up under SMP > here), and the Xenomai tests, including the last instrumentation, ran in > SMP mode. So I tend to exclude SMP effects. > > Do you have some suggestion how to analyse what the guest is executing > while thos

Re: [kvm-devel] High vm-exit latencies during kvm boot-up/shutdown

Avi Kivity wrote: > Jan Kiszka wrote: >>> Exiting on a pending interrupt is controlled by the vmcs word >>> PIN_BASED_EXEC_CONTROL, bit PIN_BASED_EXT_INTR_MASK. Can you check (via >>> vmcs_read32()) that the bit is indeed set? >>> >>> [if not, a guest can just enter a busy loop and kill a processo

Re: [kvm-devel] High vm-exit latencies during kvm boot-up/shutdown

Jan Kiszka wrote: > >> Exiting on a pending interrupt is controlled by the vmcs word >> PIN_BASED_EXEC_CONTROL, bit PIN_BASED_EXT_INTR_MASK. Can you check (via >> vmcs_read32()) that the bit is indeed set? >> >> [if not, a guest can just enter a busy loop and kill a processor] >> >> > > I tra

Re: [kvm-devel] High vm-exit latencies during kvm boot-up/shutdown

Avi Kivity wrote: > Jan Kiszka wrote: >> Avi Kivity wrote: >>> Please post a disassembly of your vmx_vcpu_run so we can interpret the >>> offsets. >>> >> Here it comes: >> >> 2df0 : >> 2df0: 55 push %ebp >> 2df1: 89 e5 mov%es

Re: [kvm-devel] High vm-exit latencies during kvm boot-up/shutdown

Jan Kiszka wrote: > Avi Kivity wrote: > >> Jan Kiszka wrote: >> >>> Avi, >>> >>> [somehow your mails do not get through to my private account, so I'm >>> switching] >>> >>> Avi Kivity wrote: >>> >>> Jan Kiszka wrote: > Clarification: I can't precis

Re: [kvm-devel] High vm-exit latencies during kvm boot-up/shutdown

Gregory Haskins wrote: > On Tue, 2007-10-23 at 16:19 +0200, Avi Kivity wrote: >> Jan Kiszka wrote: >>> Avi, >>> >>> [somehow your mails do not get through to my private account, so I'm >>> switching] >>> >>> Avi Kivity wrote: >>> Jan Kiszka wrote: > Clarification: I can't prec

Re: [kvm-devel] High vm-exit latencies during kvm boot-up/shutdown

On Tue, 2007-10-23 at 16:19 +0200, Avi Kivity wrote: > Jan Kiszka wrote: > > Avi, > > > > [somehow your mails do not get through to my private account, so I'm > > switching] > > > > Avi Kivity wrote: > > > >> Jan Kiszka wrote: > >> > >>> Clarification: I can't precisely tell what code is ex

Re: [kvm-devel] High vm-exit latencies during kvm boot-up/shutdown

Jan Kiszka wrote: > Avi Kivity wrote: >> Seeing vmx_vcpu_run() in there confuses me, as it always runs with >> interrupts disabled (it does dispatch NMIs, so we could be seeing an NMI). > > The point is that the cyclictest does not find large latencies when kvm > is not happening to start or stop

Re: [kvm-devel] High vm-exit latencies during kvm boot-up/shutdown

Avi Kivity wrote: > Jan Kiszka wrote: >> Avi, >> >> [somehow your mails do not get through to my private account, so I'm >> switching] >> >> Avi Kivity wrote: >> >>> Jan Kiszka wrote: >>> Clarification: I can't precisely tell what code is executed in VM mode, as I don't have qemu

Re: [kvm-devel] High vm-exit latencies during kvm boot-up/shutdown

Jan Kiszka wrote: > Avi, > > [somehow your mails do not get through to my private account, so I'm > switching] > > Avi Kivity wrote: > >> Jan Kiszka wrote: >> >>> Clarification: I can't precisely tell what code is executed in VM mode, >>> as I don't have qemu or that guest instrumented. I j

Re: [kvm-devel] High vm-exit latencies during kvm boot-up/shutdown

Avi, [somehow your mails do not get through to my private account, so I'm switching] Avi Kivity wrote: > Jan Kiszka wrote: >> Clarification: I can't precisely tell what code is executed in VM mode, >> as I don't have qemu or that guest instrumented. I just see the kernel >> entering VM mode and l

Re: [kvm-devel] High vm-exit latencies during kvm boot-up/shutdown

Jan Kiszka wrote: > Clarification: I can't precisely tell what code is executed in VM mode, > as I don't have qemu or that guest instrumented. I just see the kernel > entering VM mode and leaving it again more than 300 us later. So I > wonder why this is allowed while some external IRQ is pending.

Re: [kvm-devel] High vm-exit latencies during kvm boot-up/shutdown

Dong, Eddie wrote: > > >> -Original Message- >> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] >> Sent: 2007年10月23日 14:38 >> To: Dong, Eddie >> Cc: kvm-devel@lists.sourceforge.net >> Subject: Re: [kvm-devel] High vm-exit latencies during

Re: [kvm-devel] High vm-exit latencies during kvm boot-up/shutdown

Jan Kiszka wrote: > Dong, Eddie wrote: > >> [EMAIL PROTECTED] wrote: >> >>> Hi, >>> >>> I'm seeing fairly high vm-exit latencies (300-400 us) during and only >>> during qemu/kvm startup and shutdown on a Core2 T5500 in 32-bit mode. >>> It's most probably while the VM runs inside bios code.

Re: [kvm-devel] High vm-exit latencies during kvm boot-up/shutdown

>-Original Message- >From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] >Sent: 2007年10月23日 14:38 >To: Dong, Eddie >Cc: kvm-devel@lists.sourceforge.net >Subject: Re: [kvm-devel] High vm-exit latencies during kvm >boot-up/shutdown > >Dong, Eddie wrote: >>

Re: [kvm-devel] High vm-exit latencies during kvm boot-up/shutdown

Dong, Eddie wrote: > [EMAIL PROTECTED] wrote: >> Hi, >> >> I'm seeing fairly high vm-exit latencies (300-400 us) during and only >> during qemu/kvm startup and shutdown on a Core2 T5500 in 32-bit mode. >> It's most probably while the VM runs inside bios code. During the rest >> of the time, while s

Re: [kvm-devel] High vm-exit latencies during kvm boot-up/shutdown

[EMAIL PROTECTED] wrote: > Hi, > > I'm seeing fairly high vm-exit latencies (300-400 us) during and only > during qemu/kvm startup and shutdown on a Core2 T5500 in 32-bit mode. > It's most probably while the VM runs inside bios code. During the rest > of the time, while some Linux guest is running