freebsd kernel with SKQ
ef1856bb83
avoid substantial potential bloat for static binaries that do not
otherwise use any printf(3)-family functions. [1]
Rearrange arena_run_t so that the region bitmask can be minimally sized
according to constraints related to each bin's size class. Previously,
the region bitmask was the same size for all run headers, which wasted
a measurable amount of memory.
Rather than making runs for small objects as large as possible, make
runs as small as possible such that header overhead stays below a
certain bound. There are two exceptions that override the header
overhead bound:
1) If the bound is impossible to honor, it is relaxed on a
per-size-class basis. Since there is one bit of header
overhead per object (plus a constant), it is impossible to
achieve a header overhead less than or equal to 1/(# of bits
per object). For the current setting of maximum 0.5% header
overhead, this relaxation comes into play for {2, 4, 8,
16}-byte objects, for which header overhead is (on 64-bit
systems) {7.1, 4.3, 2.2, 1.2}%, respectively.
2) There is still a cap on small run size, still set to 64kB.
This comes into play for {1024, 2048}-byte objects, for which
header overhead is {1.6, 3.1}%, respectively.
In practice, this reduces the run sizes, which makes worst case
low-water memory usage due to fragmentation less bad. It also reduces
worst case high-water run fragmentation due to non-full runs, but this
is only a constant improvement (most important to small short-lived
processes).
Reduce the default chunk size from 2MB to 1MB. Benchmarks indicate that
the external fragmentation reduction makes 1MB the new sweet spot (as
small as possible without adversely affecting performance).
Reported by: [1] kientzle
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| bin | ||
| contrib | ||
| crypto | ||
| etc | ||
| games | ||
| gnu | ||
| include | ||
| kerberos5 | ||
| lib | ||
| libexec | ||
| release | ||
| rescue | ||
| sbin | ||
| secure | ||
| share | ||
| sys | ||
| tools | ||
| usr.bin | ||
| usr.sbin | ||
| COPYRIGHT | ||
| LOCKS | ||
| MAINTAINERS | ||
| Makefile | ||
| Makefile.inc1 | ||
| ObsoleteFiles.inc | ||
| 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 ``world'' target should only be used in cases where the source tree has not changed from the currently running version. See: http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/makeworld.html for more information, including setting make(1) variables. 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. rescue Build system for statically linked /rescue utilities. 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