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maps-mpls
Mentor
Mentor
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Registered: ‎06-20-2017

Slow sftp / dropbear on MPSoC /RFSoC

Does anybody know the bottle neck for sftp to an MPSoC / RFSoC?  I get about 14-15 MB/sec over a 1G interface to a RAMDISK.

Is there some secret setting to speed this up?

For comparison, for PC to PC I get about 54 MB/sec on the same 1G internal network.

*** Destination: Rapid design and development cycles *** Unappreciated answers get deleted, unappreciative OPs get put on ignored list ***
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rfs613
Scholar
Scholar
110 Views
Registered: ‎05-28-2013

With the caveat that I don't have MPSoC/RFSoc, only older Zynq-7000 devices: you are probably seeing limits of CPU doing the encryption/decryption on each packet. On a PC with many GHz processor this overhead is much less.

To check if this is happening, I would suggest testing with a non-encrypted protocol - for example plain FTP, plain HTTP (wget/curl). There are also dedicated tools like iperf3 that can be used to measure throughput. Using iperf3 between PCs, I get around 117 MB/sec, which is pretty much the full speed of 1G ethernet. The same test on an ~1GHz ARM device only reaches 70 MB/sec (of course, this depends on a lot of factors, so YMMV).

If you need to use SFTP, then you could look into whether there is any crypto-hw acceleration available on your platform, and whether sftp can make use of it.

maps-mpls
Mentor
Mentor
35 Views
Registered: ‎06-20-2017

@rfs613 It looks like dropbear is a single threaded application and it is consuming 100% of one of the application processors.   In comparison, copy within the embedded system to / from a sata drive is about 150-170 MB/sec.  So I guess you're right...the crypto is probably slowing things down.

*** Destination: Rapid design and development cycles *** Unappreciated answers get deleted, unappreciative OPs get put on ignored list ***
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