Dear SMC Maintainers and Contributors, I would like to bring to your attention some observations made during recent experiments conducted with the SMC-R on the following system: - SMC version: 3E92E1460DA96BE2B2DDC2F (version 1) - Kernel: both v5.4 and v5.15 - Ubuntu: 20.04 - Benchmarking tool: ‘qperf’ - The SMC-R vs TCP/IP throughput has been measured using the ‘qperf’ tool for various message sizes ranging from 0 to 8 MB. Based on the attached plot, you may notice that the SMC-R throughput drops substantially according to a periodic regular pattern. A few configurations have been checked, but the pattern described above persists: - All the min/default/max values of ‘net.ipv4.tcp_rmem’ and ‘net.ipv4.tcp_wmem’ have been utilized. - Experiments with the Linux kernel v5.4 and v5.15 have been conducted. - The MTU size has been changed from 1500 up to 9000. - Several message sizes have been tried. I was wondering whether you could help me understand a reason behind these drops, please? This behavior is not observed with the TCP/IP stack. Any insights or guidance would be highly appreciated. Thank you very much in advance. Mit freundlichen Grüßen / Best regards Alexandros Nikolaou Bosch Service Solutions Magdeburg GmbH | Otto-von-Guericke-Str. 13 | 39104 Magdeburg | GERMANY | [www.boschservicesolutions.com]www.boschservicesolutions.com Alexandros.Nikolaou@xxxxxxxxxxxx Sitz: Magdeburg, Registergericht: Amtsgericht Stendal, HRB 24039 Geschäftsführung: Robert Mulatz, Daniel Meyer
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