Date: Fri, 26 May 2017 21:57:16 +0000 From: Rick Macklem <rmacklem@uoguelph.ca> To: "freebsd-current@freebsd.org" <freebsd-current@freebsd.org> Subject: NFS client perf. degradation when SCHED_ULE is used (was when SMP enabled) Message-ID: <YTXPR01MB01894DA2879C95E634C792D9DDFC0@YTXPR01MB0189.CANPRD01.PROD.OUTLOOK.COM>
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To briefly summarize the previous post related to perf. degradation when running a recent kernel... - kernel build running 1yr old kernel took 100minutes - same kernel build running recent kernel 148minutes (ie. Almost a 50% degradation.) As noted in the last post, I got rid of most of the degradation by disabling SMP. - same kernel build running recent kernel with SCHED_4BSD 104minutes I have now found I can get rid of almost all of the degradation by building the recent kernel with options SCHED_4BSD instead of options SCHED_ULE The 1yr old kernel was built with SCHED_ULE, so the degradation is some change to the kernel since Apr. 12, 2016 that affects SCHED_ULE but not SCHED_4BSD. Any ideas? Since GENERIC uses SCHED_ULE, it would be nice to see good perf. with that option. However, recommending "options SCHED_4BSD" is nicer than recommending disabling SMP;-) rick ps: I tried the 1yr old net driver in the recent kernel and it had no effect on perf.help
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