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cmartin
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Number of CPU cores on CRS3xx

Tue Jan 04, 2022 4:30 pm

Hello,
after upgrade of some CRS's to 7.1+ I see output like this:
/system/resource/print 
                   uptime: 4d3h38m12s
                  version: 7.1.1 (stable)
               build-time: Dec/21/2021 11:53:05
         factory-software: 6.38.2
              free-memory: 448.6MiB
             total-memory: 512.0MiB
                      cpu: ARMv7
                cpu-count: 2
                 cpu-load: 2%
           free-hdd-space: 2380.0KiB
          total-hdd-space: 16.0MiB
  write-sect-since-reboot: 3113
         write-sect-total: 904955
               bad-blocks: 0%
        architecture-name: arm
               board-name: CRS326-24G-2S+
                 platform: MikroTik
or this
/system/resource/print 
                   uptime: 1w4d23h2m43s
                  version: 7.1.1 (stable)
               build-time: Dec/21/2021 11:53:05
         factory-software: 6.41.3
              free-memory: 440.4MiB
             total-memory: 512.0MiB
                      cpu: ARMv7
                cpu-count: 2
                 cpu-load: 8%
           free-hdd-space: 1516.0KiB
          total-hdd-space: 16.0MiB
  write-sect-since-reboot: 38339
         write-sect-total: 992844
               bad-blocks: 0%
        architecture-name: arm
               board-name: CRS328-24P-4S+
                 platform: MikroTik
here I would like to point your attention to field "cpu-count" above. Is number "2" there false positive or actual number of cores?
As far as I remember, in RouterOS 6.x was only one core there and documentation also says that those devices should be single-core ...

Have a nice day
Martin
 
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Re: Number of CPU cores on CRS3xx

Tue Jan 04, 2022 5:09 pm

This seems like a bug unless CRS326 switches have been moved to a newer CPU

https://mikrotik.com/product/crs326_24g ... ifications
 
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Paternot
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Re: Number of CPU cores on CRS3xx

Tue Jan 04, 2022 5:51 pm

They are dual core. RoS 6 could only see one of them, so they were sold as single core - but RoS 7 can see (and use) both of them.
 
biomesh
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Re: Number of CPU cores on CRS3xx

Tue Jan 04, 2022 5:53 pm

According to the following PDF, they are dual core. I am guessing the updated kernel in v7 allowed for the use of both cores vs the v6 kernel.

https://wifimag.ro/pdf/Prestera_98DX3336_pb.pdf
 
cmartin
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Re: Number of CPU cores on CRS3xx

Tue Jan 04, 2022 7:02 pm

Excellent! Sound like Christmas gift from MikroTik ;)
M.
 
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Re: Number of CPU cores on CRS3xx

Tue Jan 04, 2022 10:29 pm

They are dual core. RoS 6 could only see one of them, so they were sold as single core - but RoS 7 can see (and use) both of them.
That would be somewhat strange, though I wonder if other 3236 devices are affected - CRS305 and various CRS328 devices?
 
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Re: Number of CPU cores on CRS3xx

Tue Jan 04, 2022 11:08 pm

They are dual core. RoS 6 could only see one of them, so they were sold as single core - but RoS 7 can see (and use) both of them.
That would be somewhat strange, though I wonder if other 3236 devices are affected - CRS305 and various CRS328 devices?
If I remember correctly, the CRS328-24P-4S+RM is dual core too. Don't know about the others.
 
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Re: Number of CPU cores on CRS3xx

Tue Jan 04, 2022 11:18 pm

They are dual core. RoS 6 could only see one of them, so they were sold as single core - but RoS 7 can see (and use) both of them.
That would be somewhat strange ...
Why do you find it strange? Back when linux kernel 3.3 was condidered modern, it was still sensible to build a kernel with minimum supported feature set ... e.g. support for single CPU (core), support for 4GB RAM (take away address space for hardware and one ends up supporting 2GB RAM), .... Specially so if support for SMP on ARM was not really stable at that time ...

Keep in mind that ROS v7 ships with linux kernel which is 10 years younger than in ROS v6 ... for any architecture actively supported in stock linux kernel except for x86 and x64 that's difference between modern and stone age.
 
cmartin
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Re: Number of CPU cores on CRS3xx

Wed Jan 05, 2022 9:29 am

...
If I remember correctly, the CRS328-24P-4S+RM is dual core too
It seems it is - see second output in first post
 
glow
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Re: Number of CPU cores on CRS3xx

Wed Jan 05, 2022 3:07 pm



That would be somewhat strange ...
Why do you find it strange? Back when linux kernel 3.3 was condidered modern, it was still sensible to build a kernel with minimum supported feature set ... e.g. support for single CPU (core), support for 4GB RAM (take away address space for hardware and one ends up supporting 2GB RAM), .... Specially so if support for SMP on ARM was not really stable at that time ...

Keep in mind that ROS v7 ships with linux kernel which is 10 years younger than in ROS v6 ... for any architecture actively supported in stock linux kernel except for x86 and x64 that's difference between modern and stone age.
Strange, since there are already other dual core devices within the CRS3xx lineup. I have one (CRS309), and it was a dual core under ROS6 as well. Why would some be offered as dual cores and others as single core, if many were dual core to begin with? I won't tend to the other CRS3xx devices that have a switch chip, then an ancient Qualcomm WiFi SoC running as the "CPU," attached via a 1Gbps Ethernet port.
 
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Re: Number of CPU cores on CRS3xx

Wed Jan 05, 2022 3:35 pm

Those with dual core support were a different chipset 98dx82xx series vs 98dx3236.

My guess is that kernel support for the 98dx3236 was not complete with the old kernel in 6x
 
Guscht
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Re: Number of CPU cores on CRS3xx

Sun Aug 07, 2022 1:14 am

Interesting, same CPU (98DX3236) https://wifimag.ro/pdf/Prestera_98DX3336_pb.pdf
same ROS, different cores...

CRS326
326-1.jpg
326-2.jpg

CRS328
328-1.jpg
328-2.jpg
You do not have the required permissions to view the files attached to this post.
 
tangent
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Re: Number of CPU cores on CRS3xx

Sun Aug 07, 2022 1:41 am

Interesting, same CPU (98DX3236) https://wifimag.ro/pdf/Prestera_98DX3336_pb.pdf
same ROS, different cores...

Running the CPU in 2-core mode caused SFP instability. (I saw it here.) They fixed it in 7.4: "disabled second CPU core for CRS328-24P-4S+ device in order to improve SFP+ link stability."

MikroTik isn't saying what the cause was, but the prevailing hypothesis in the relevant thread is that they've been buying 2-core processors that were binned as 1-core processors due to a manufacturing flaw. Enabling the broken second core caused the flaw to be hit, harming overall performance.

They now advertise a single core, regardless of whether the processor family has 2-core options, because that's what RouterOS runs them as.

If you want to go back to the old versions of RouterOS that supported 2 cores, they're still available, but watch out for that SFP+ instability! Starting from 7.1 and going to 7.3.1, you have 7 months of broken releases to pick from. Enjoy. :)
 
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Re: Number of CPU cores on CRS3xx

Sun Aug 07, 2022 10:04 pm

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