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Post by ctschorsch on Oct 17, 2018 10:47:11 GMT
Dear all,
i have some performance issues on an control computer for a scientific instrument and want to use SIV to get some more informations.
background:
the control computer is a rugged VPX 3U chassis with a i7 CPU Board, connected with 8x PCIe Gen 2 to a backplane with an 8x PCIe switch on it. a PCIe to SATA II Carrier and an 10G Ethernet card is also connected to the backplane.
the PCIe to SATA II Carrier should deliver about 250MByte/s to the CPU (1x PCIe Gen 1, SATA 2) but a maximum of 110MB is reached the 10G Ethernet reaches 400MByte/s (SIV shows me 4x PCIe Gen 1. negotiated)
question: Is it possible to see the real bandwith on a single PCIe lane ? I dont know where the bottleneck is...
Thanks Regards Georg
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Post by siv on Oct 17, 2018 11:18:49 GMT
Hi,
The SIV [PCI Bus] panel reports the negotiated and maximum lanes + speeds for all the PCIe devices and from this you should be able to work out where any issues are.
From what you have posted I can't work out the topology and to have any chance of anyone helping then I expect you need to post the [PCI Bus] screen shot. I also suggest posting the initial SIV screen so we know the precise CPU information as i7 could be any one of many tens of CPUs.
Regards, Ray
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Post by ctschorsch on Oct 17, 2018 12:57:33 GMT
Hi Ray,
thanks for your reply. I know it is not a SIV problem at all, so thanks again.
Yes, all negotiated links and speed are okay, this displays SIV in a very good view. I suppose that the PCIe switch on the backplane (IDT Chip) can not handle the link with the negotiated speed
The topology is a little bit strange:
4 lanes come from the cpu 4 lanes come from the chipset
this 8 lanes go to the IDT 8x PCIe switch on the backplane
from there 1 lane got to the SATA controller and 4 lanes to the ethernet controller
Thanks Georg
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Post by siv on Oct 17, 2018 16:00:43 GMT
the PCIe to SATA II Carrier should deliver about 250MByte/s to the CPU (1x PCIe Gen 1, SATA 2) but a maximum of 110MB is reached the 10G Ethernet reaches 400MByte/s (SIV shows me 4x PCIe Gen 1. negotiated) Given the 10GBe has 4 lanes and is about 4 times the speed of the single lane SATA that is what I would expect. I suspect to get the information you would like you will need a PCIe analyser such as spam://teledynelecroy.com/protocolanalyzer/pci-express, but you really need help from someone who knows rather more about how PCIe works than I do. I am wondering why SIV did not report the disk drive temperature, I guess it's not in the SMART data. If you press Shift and Left/Click the blob what does the SMART details panel report?
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Post by ctschorsch on Oct 18, 2018 10:46:11 GMT
which blob should i click ?
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Post by siv on Oct 19, 2018 18:09:53 GMT
which blob should i click ? The one for the disk, it also has a tooltip. Attachments:
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