freebsd with flexible iflib nic queues
fc271df341
"qsort()". The kernel's "qsort()" routine can in worst case spend O(N*N) amount of comparisons before the input array is sorted. It can also recurse a significant amount of times using up the kernel's interrupt thread stack. The custom sorting routine takes advantage of that the sorting key is only 64 bits. Based on set and cleared bits in the sorting key it partitions the array until it is sorted. This process has a recursion limit of 64 times, due to the number of set and cleared bits which can occur. Compiled with -O2 the sorting routine was measured to use 64-bytes of stack. Multiplying this by 64 gives a maximum stack consumption of 4096 bytes for AMD64. The same applies to the execution time, that the array to be sorted will not be traversed more than 64 times. When serving roughly 80Gb/s with 80K TCP connections, the old method consisting of "qsort()" and "tcp_lro_mbuf_compare_header()" used 1.4% CPU, while the new "tcp_lro_sort()" used 1.1% for LRO related sorting as measured by Intel Vtune. The testing was done using a sysctl to toggle between "qsort()" and "tcp_lro_sort()". Differential Revision: https://reviews.freebsd.org/D6472 Sponsored by: Mellanox Technologies Tested by: Netflix Reviewed by: gallatin, rrs, sephe, transport |
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| 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