<div dir="ltr"><div class="gmail_default" style="font-family:tahoma,sans-serif">Hi,<br></div><div class="gmail_default" style="font-family:tahoma,sans-serif">I am using a Centos 7 where the default kernel version is 3.10. I have installed that on a VirtualBox as a test system. Then I decided to upgrade the kernel to 4.15 with the elrepo packages.<br><br></div><div class="gmail_default" style="font-family:tahoma,sans-serif">With the NAS parallel benchmark suite, I have noticed some performance degradation. The runtime is about one minute longer with 4.15. I know that this using VirtualBox is not a good infrastructure for performance measurements, but may be can be used as a hint.<br><br></div><div class="gmail_default" style="font-family:tahoma,sans-serif">See the results below<br><br></div><div class="gmail_default" style="font-family:tahoma,sans-serif">Kernel-3.10<br> bt.C.4 => 698.12 sec<br> ep.D.4 => 2561.44 sec<br> cg.C.2 => 187.96 sec<br> ft.C.2 => 288.49 sec<br> ft.C.4 => 160.72 sec<br> lu.C.4 => 541.46 sec<br> lu.D.4 => 12705.02 sec<br><br></div><div class="gmail_default" style="font-family:tahoma,sans-serif">Kernel-4.15<br> bt.C.4 => 746.17 sec<br> ep.D.4 => 2510.52 sec<br> cg.C.2 => 209.17 sec<br> ft.C.2 => 284.43 sec<br> ft.C.4 => 155.67 sec<br> lu.C.4 => 646.67 sec<br> lu.D.4 => 16930.73 sec<br><br></div><div class="gmail_default" style="font-family:tahoma,sans-serif">Any idea?<br><br clear="all"></div><div><div class="gmail_signature"><div dir="ltr"><font face="tahoma,sans-serif">Regards,<br>Mahmood</font><br><br><br></div></div></div>
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