Date: Wed, 30 Aug 2017 14:24:30 +0200 From: Jan Bramkamp <crest@rlwinm.de> To: freebsd-arch@freebsd.org Subject: Re: ULE steal_idle questions Message-ID: <eb6da256-486f-5c65-6014-2a2245c1bccf@rlwinm.de> In-Reply-To: <201708261958.v7QJwbGK054320@gw.catspoiler.org> References: <201708261958.v7QJwbGK054320@gw.catspoiler.org>
next in thread | previous in thread | raw e-mail | index | archive | help
On 26.08.17 21:58, Don Lewis wrote: > On 26 Aug, To: kostikbel@gmail.com wrote: >> On 26 Aug, Konstantin Belousov wrote: >>> On Sat, Aug 26, 2017 at 11:29:29AM -0700, Don Lewis wrote: >>>> I actually haven't noticed that problem on my package build boxes. I've >>>> experienced decent interactive performance even when the load average is >>>> in the 60 to 80 range. I also have poudriere configured to use tmpfs >>>> and the only issue I run into is when it starts getting heavily into >>>> swap (like 20G) and I leave my session idle for a while, which lets my >>>> shell and sshd get swapped out. Then it takes them a while to wake up >>>> again. Once they are paged in, then things feel snappy again. This is >>>> remote access, so I can't comment on what X11 feels like. >>> I believe what people complain about is the following scenario: >>> they have some interactive long living process, say firefox or mplayer. >>> The process' threads consume CPU cycles, so the ULE interactivity >>> detection logic actually classifies the threads as non-interactive. >>> >>> This is not much problematic until a parallel build starts where >>> toolchain processes are typically short-lived. This makes them >>> classified as interactive, and their dynamic priority are lower than the >>> priority of long-lived threads which are interactive by user perception. >>> >>> I did not analyzed the KTR dumps but this explanation more or less >>> coincides with the system slugginess when attempt to use mplayer while >>> heavily oversubscribed build (e.g. make -j 10 on 4 cores x 2 SMT >>> machine) is started. >> I can believe that. I keep an excessive number of tabs open in firefox >> and it would frequenty get into a state where it would consume 100% of a >> CPU core. Very recent versions of firefox are a lot better. >> >> Xorg is another possible victim. I've just noticed that when certain >> windows have mouse focus (firefox being one, wish-based apps are >> another) that the Xorg %CPU goes to 80%-90%. I think this crept in with >> the lastest MATE upgrade. If Xorg is treated as non-interactive, then >> the desktop experience is going to be less than optimal if there is >> competing load. > I've got poudriere running right now on my primary package build box. > The priorties of the compiler processes are currently in the range of > 74-96. > > On my desktop, firefox is running at priority 24. Xorg when it is not > being a CPU hog gets all the way down to priority 20. When the mouse is > pointing to one of the windows that makes it go nuts, then it gets all > the way up to priority 98. On my old desktop (AMD Phenom II X6 1060T) which doubled as poudriere compile server I wrapped Xorg and moused with cpuset and rtprio. It solved my problem, but felt wrong.
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?eb6da256-486f-5c65-6014-2a2245c1bccf>