Date: Sun, 6 Jul 2014 15:33:59 +0300 From: Konstantin Belousov <kostikbel@gmail.com> To: Stefan Parvu <sparvu@systemdatarecorder.org> Cc: freebsd-hackers@freebsd.org Subject: Re: run-queue length question Message-ID: <20140706123359.GD93733@kib.kiev.ua> In-Reply-To: <20140706143212.3d22d0adfa5dece52de203a3@systemdatarecorder.org> References: <20140706143212.3d22d0adfa5dece52de203a3@systemdatarecorder.org>
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[-- Attachment #1 --] On Sun, Jul 06, 2014 at 02:32:12PM +0300, Stefan Parvu wrote: > Hi, > > Im trying to understand what FreeBSD kernel counts for run-queue length. > > Traditional we count as queue length: number of processes which are running plus > the number that are runnable (waiting to execute) - we *dont* count processes waiting > for storage, network etc. > > Linux kernel has added into run-queue length the iowait processes which makes > load average values big and disproportionate to the reality for example during > disk io tests. > > How does FreeBSD handle this part ? Is the queue length simple the number of > running processes + waiting to run or not as we used to have in UNIX world ? It is the Linux which follows the traditional definition of the load, by counting running, ready to run and 'blocked on the fast i/o' processes as adding to the load average. Also, I remember that FreeBSD up to 4.x followed this definition. Sometime during the 5.x rewrites the load was redefined to only count running + ready to run threads, which is the current definition, used by LA. [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQIcBAEBAgAGBQJTuUI3AAoJEJDCuSvBvK1BBTAP/2rodsb979Wc3jEbC2zDxHXN WOa9thboYfLf7JRaicBS9ydyO0NPtHhg4B2GDhBdbQ4DYUwPaBqa+EGuyuhhVR4V YaPUzWt8wxezX24H2+VkZiJxfL/tMmo+EEHYEFPPlsfZSc/IGL1csCwLASjYrqZ0 dSRSaF5Omm/wmt3MNUIgIQgCtL5Ik++f7RxkvuTuyNS8p1SYLWa/3/RefMJwywkX fO76q8HgRdm3Q9DYqCOFxvlaapnVpNWNa4YvJg82BUz0T+l01jjly5xt8CuPJ+MW YVKJPE04lnr4pzQTVjqHPAqY6juFoz/KWx+qfbM9XBhLvjLss+S22zWIGOIiywzT C00uDh16jUrddrQ5Rfk27JhBtR83L9+5LacOpTFgxu5q4YoZ8m0DXSHjAVmBHDCL 9wb+dDIbPOT/HNIkT4wQ9YNrgdl4deoE+yF9XIhH+Zlh+RkPHkLa1Csdh3+1gbrE EzstgI8r3kiHct/WZgvPkkOSDrgtncxnHzYucN9/ATBFHNccKYlMtjqtceTBgib3 R0VUZXBe8WYEUBeiUfA6HT8RwtcN9eqvjNN5hMc6yHZ9aTkx38AALw6RvXnApQk3 RF4C4kp05j0FhhEdOjaI7BbnNSoGpFEtl1fNX2tL0Vq4bbrcp700ebro4DW8uBAV kogQIcJJx7t5vLxY3ust =wU+P -----END PGP SIGNATURE-----help
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