Thank you a lot for the tip - you were right. The 5.5 guest is using virtio, but 4.5 is not. So, this is the reason. Adding <model type='virtio' /> to the config file unfortunately doesn't help - the network card is not recognized by the guest. Do I need to install something extra on the guest RHEL 4.5? Regards, Alex On Tue, Aug 17, 2010 at 12:05 AM, Alex Rixhardson <alexrixhardson@xxxxxxxxx> wrote: > virtio...I think :-). > > How could I confirm that? > > Regards, > Alex > > On Mon, Aug 16, 2010 at 11:56 PM, Dor Laor <dlaor@xxxxxxxxxx> wrote: >> On 08/17/2010 12:51 AM, Alex Rixhardson wrote: >>> >>> I tried with 'notsc divider=10' (since it's 64 bit guest), but the >>> results are the still same :-(. The guest is idle at the time of >>> testing. It has 2 CPU and 1024 MB RAM available. >> >> Hmm, are you using e1000 or virtio for the 4.5 guest? >> e1000 should be slow since it's less suitable for virtualization (3 >> mmio/packet) >> >> >>> >>> On Mon, Aug 16, 2010 at 11:35 PM, Dor Laor<dlaor@xxxxxxxxxx> wrote: >>>> >>>> On 08/17/2010 12:22 AM, Alex Rixhardson wrote: >>>>> >>>>> Thanks for the suggestion. >>>>> >>>>> I tried with the netperf. I ran netserver on host and netperf on RHEL >>>>> 5.5 and RHEL 4.5 guests. This are the results of 60 seconds long >>>>> tests: >>>>> >>>>> RHEL 4.5 guest: >>>>> Throughput (10^6bits/sec) = 145.80 >>>> >>>> At least it bought you another 5Mb/s over iperf ... >>>> >>>> It might be time related, 5.5 has kvmclock but rhel4 does not. >>>> If it's 64 bit guest add this to the 4.5 guest cmdline 'notsc >>>> divider=10'. >>>> If it's 32 use 'clock=pmtmr divider=10'. >>>> The divider is probably new and is in rhel4.8 only, it's ok w/o it too. >>>> >>>> What's the host load for the 4.5 guest? >>>> >>>>> >>>>> RHEL 5.5 guest: >>>>> Throughput (10^6bits/sec) = 3760.24 >>>>> >>>>> The results are really bad on RHEL 4.5 guest. What could be wrong? >>>>> >>>>> Regards, >>>>> Alex >>>>> >>>>> On Mon, Aug 16, 2010 at 9:49 PM, Dor Laor<dlaor@xxxxxxxxxx> wrote: >>>>>> >>>>>> On 08/16/2010 10:00 PM, Alex Rixhardson wrote: >>>>>>> >>>>>>> Hi guys, >>>>>>> >>>>>>> I have the following configuration: >>>>>>> >>>>>>> 1. host is RHEL 5.5, 64bit with KVM (version that comes out of the box >>>>>>> with RHEL 5.5) >>>>>>> 2. two guests: >>>>>>> 2a: RHEL 5.5, 32bit, >>>>>>> 2b: RHEL 4.5, 64bit >>>>>>> >>>>>>> If I run iperf between host RHEL 5.5 and guest RHEL 5.5 inside the >>>>>>> virtual network subnet I get great results (> 4Gbit/sec). But if >>>>>>> I >>>>>>> run >>>>>>> iperf between guest RHEL 4.5 and either of the two RHELs 5.5 I get bad >>>>>>> network performance (around 140Mbit/sec). >>>>>> >>>>>> Please try netperf, iperf known to be buggy and might consume cpu w/o >>>>>> real >>>>>> justification >>>>>> >>>>>>> >>>>>>> The configuration was made thru virtual-manager utility, nothing >>>>>>> special. I just added virtual network device to both guests. >>>>>>> >>>>>>> Could you guys give me some tips on what should I check? >>>>>>> >>>>>>> Regards, >>>>>>> Alex >>>>>>> -- >>>>>>> To unsubscribe from this list: send the line "unsubscribe kvm" in >>>>>>> the body of a message to majordomo@xxxxxxxxxxxxxxx >>>>>>> More majordomo info at http://vger.kernel.org/majordomo-info.html >>>>>> >>>>>> >>>>> -- >>>>> To unsubscribe from this list: send the line "unsubscribe kvm" in >>>>> the body of a message to majordomo@xxxxxxxxxxxxxxx >>>>> More majordomo info at http://vger.kernel.org/majordomo-info.html >>>> >>>> >>> -- >>> To unsubscribe from this list: send the line "unsubscribe kvm" in >>> the body of a message to majordomo@xxxxxxxxxxxxxxx >>> More majordomo info at http://vger.kernel.org/majordomo-info.html >> >> > -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
