mirror of
https://github.com/opnsense/src.git
synced 2026-04-09 11:27:18 -04:00
OPNsense - FreeBSD source
b698380f33
in the log message for kern_sched.c 1.83 (which should have been repo-copied to preserve history for this file), the (4BSD) scheduler algorithm only works right if stathz is nearly 128 Hz. The old commit lock said 64 Hz; the scheduler actually wants nearly 16 Hz but there was a scale factor of 4 to give the requirement of 64 Hz, and rev.1.83 changed the scale factor so that the requirement became 128 Hz. The change of the scale factor was incomplete in the SMP case. Then scheduling ticks are provided by smp_ncpu CPUs, and the scheduler cannot tell the difference between this and 1 CPU providing scheduling ticks smp_ncpu times faster, so we need another scale factor of smp_ncp or an algorithm change. This quick fix uses the scale factor without even trying to optimize the runtime divisions required for this as is done for the other scale factor. The main algorithmic problem is the clamp on the scheduling tick counts. This was 295; it is now approximately 295 * smp_ncpu. When the limit is reached, threads get free timeslices and scheduling becomes very unfair to the threads that don't hit the limit. The limit can be reached and maintained in the worst case if the load average is larger than (limit / effective_stathz - 1) / 2 = 0.65 now (was just 0.08 with 2 CPUs before this change), so there are algorithmic problems even for a load average of 1. Fortunately, the worst case isn't common enough for the problem to be very noticeable (it is mainly for niced CPU hogs competing with less nice CPU hogs). |
||
|---|---|---|
| bin | ||
| contrib | ||
| crypto | ||
| etc | ||
| games | ||
| gnu | ||
| include | ||
| kerberos5 | ||
| lib | ||
| libexec | ||
| release | ||
| rescue | ||
| sbin | ||
| secure | ||
| share | ||
| sys | ||
| tools | ||
| usr.bin | ||
| usr.sbin | ||
| COPYRIGHT | ||
| MAINTAINERS | ||
| Makefile | ||
| Makefile.inc1 | ||
| README | ||
| UPDATING | ||
This is the top level of the FreeBSD source directory. This file was last revised on: $FreeBSD$ For copyright information, please see the file COPYRIGHT in this directory (additional copyright information also exists for some sources in this tree - please see the specific source directories for more information). The Makefile in this directory supports a number of targets for building components (or all) of the FreeBSD source tree, the most commonly used one being ``world'', which rebuilds and installs everything in the FreeBSD system from the source tree except the kernel, the kernel-modules and the contents of /etc. The ``buildkernel'' and ``installkernel'' targets build and install the kernel and the modules (see below). Please see the top of the Makefile in this directory for more information on the standard build targets and compile-time flags. Building a kernel is a somewhat more involved process, documentation for which can be found at: http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/kernelconfig.html And in the config(8) man page. Note: If you want to build and install the kernel with the ``buildkernel'' and ``installkernel'' targets, you might need to build world before. More information is available in the handbook. The sample kernel configuration files reside in the sys/<arch>/conf sub-directory (assuming that you've installed the kernel sources), the file named GENERIC being the one used to build your initial installation kernel. The file NOTES contains entries and documentation for all possible devices, not just those commonly used. It is the successor of the ancient LINT file, but in contrast to LINT, it is not buildable as a kernel but a pure reference and documentation file. Source Roadmap: --------------- bin System/user commands. contrib Packages contributed by 3rd parties. crypto Cryptography stuff (see crypto/README). etc Template files for /etc. games Amusements. gnu Various commands and libraries under the GNU Public License. Please see gnu/COPYING* for more information. include System include files. kerberos5 Kerberos5 (Heimdal) package. lib System libraries. libexec System daemons. release Release building Makefile & associated tools. sbin System commands. secure Cryptographic libraries and commands. share Shared resources. sys Kernel sources. tools Utilities for regression testing and miscellaneous tasks. usr.bin User commands. usr.sbin System administration commands. For information on synchronizing your source tree with one or more of the FreeBSD Project's development branches, please see: http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/synching.html