Date: Thu, 23 Mar 2023 13:45:41 -0700 From: Mark Millard <marklmi@yahoo.com> To: Warner Losh <imp@bsdimp.com>, FreeBSD Hackers <freebsd-hackers@freebsd.org> Subject: Re: Periodic rant about SCHED_ULE Message-ID: <24F6D88F-3F15-48FB-AA5A-AFD4B77A1D39@yahoo.com> References: <24F6D88F-3F15-48FB-AA5A-AFD4B77A1D39.ref@yahoo.com>
next in thread | previous in thread | raw e-mail | index | archive | help
Warner Losh <imp_at_bsdimp.com> wrote on Date: Wed, 22 Mar 2023 22:57:08 UTC : > On Wed, Mar 22, 2023 at 1:41=E2=80=AFPM George Mitchell = <george+freebsd@m5p.com> > wrote: >=20 > > service dnetc start > > I am literally running "make buildworld" with no additional options. > > > > > So what are the results for make buildworld -j $(sysctl -n hw.ncpu )? Note: My experiments have been in this -j $(sysctl -n hw.ncpu ) realm. > ULE scales much better, but when there's too little to do it can make = poor > choices. >=20 > ULE is better locked and don't fall over on high core count systems = like > BSD does at moderate load. (I'm presuming the above is not about the specifics of the effectively different interpretations of the likes of having extra "nice 20" activity by the two schedulers for the examples related to the original "rant", other than the -jN issue.) Any idea on what scale "high core count systems" need to be for what sort of "moderate load" to end up with signficant differences? What sort of context(s) show ULE scaling much better? On the 16 core ThreadRipper 1950X (32 hardware threads) I've really only demonstrated the "nice 20" distinction as significant between the schedulers so far. (I do not have acccess to anything with more hardware threads.) Note: I've not (yet?) been looking at having just a little more than the number of hardware threads active (no nice involvement). =3D=3D=3D Mark Millard marklmi at yahoo.com
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?24F6D88F-3F15-48FB-AA5A-AFD4B77A1D39>