freebsd kernel with SKQ
1a5735873e
for zeroing pages in idle where nontemporal writes are clearly best. This is almost a no-op since zeroing in idle works does nothing good and is off by default. Fix END() statement forgotten in previous commit. Align the loop in sse2_pagezero(). Since it writes to main memory, the loop doesn't have to be very carefully written to keep up. Unrolling it was considered useless or harmful and was not done on i386, but that was too careless. Timing for i386: the loop was not unrolled at all, and moved only 4 bytes/iteration. So on a 2GHz CPU, it needed to run at 2 cycles/ iteration to keep up with a memory speed of just 4GB/sec. But when it crossed a 16-byte boundary, on old CPUs it ran at 3 cycles/ iteration so it gave a maximum speed of 2.67GB/sec and couldn't even keep up with PC3200 memory. Fix the alignment so that it keep up with 4GB/sec memory, and unroll once to get nearer to 8GB/sec. Further unrolling might be useless or harmful since it would prevent the loop fitting in 16-bytes. My test system with an old CPU and old DDR1 only needed 5+ GB/sec. My test system with a new CPU and DDR3 doesn't need any changes to keep up ~16GB/sec. Timing for amd64: with 8-byte accesses and newer faster CPUs it is easy to reach 16GB/sec but not so easy to go much faster. The alignment doesn't matter much if the CPU is not very old. The loop was already unrolled 4 times, but needs 32 bytes and uses a fancy method that doesn't work for 2-way unrolling in 16 bytes. Just align it to 32-bytes. |
||
|---|---|---|
| bin | ||
| cddl | ||
| contrib | ||
| crypto | ||
| etc | ||
| gnu | ||
| include | ||
| kerberos5 | ||
| lib | ||
| libexec | ||
| release | ||
| rescue | ||
| sbin | ||
| secure | ||
| share | ||
| sys | ||
| targets | ||
| tests | ||
| tools | ||
| usr.bin | ||
| usr.sbin | ||
| .arcconfig | ||
| .arclint | ||
| COPYRIGHT | ||
| LOCKS | ||
| MAINTAINERS | ||
| Makefile | ||
| Makefile.inc1 | ||
| Makefile.libcompat | ||
| 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. See build(7) and 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. See build(7), config(8), and http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/kernelconfig.html for more information. 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 kernel configuration files reside in the sys/<arch>/conf sub-directory. GENERIC is the default configuration used in release builds. NOTES contains entries and documentation for all possible devices, not just those commonly used. Source Roadmap: --------------- bin System/user commands. cddl Various commands and libraries under the Common Development and Distribution License. contrib Packages contributed by 3rd parties. crypto Cryptography stuff (see crypto/README). etc Template files for /etc. 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. tests Regression tests which can be run by Kyua. See tests/README for additional information. 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