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Reuse the already implemented MurmurHash3 algorithm. Under heavy stress testing (on an 8-core system sustaining over 50,000 authentication events per second), sample once per second and take the mean of 1800 samples: 1. Bucket utilization rate and length of longest chain +--------------------------+-----------------------------------------+ | | bucket utilization rate / longest chain | | +--------------------+--------------------+ | | no-patch | with-patch | +--------------------------+--------------------+--------------------+ | 512 nodes, 512 buckets | 52.5%/7.5 | 60.2%/5.7 | +--------------------------+--------------------+--------------------+ | 1024 nodes, 512 buckets | 68.9%/12.1 | 80.2%/9.7 | +--------------------------+--------------------+--------------------+ | 2048 nodes, 512 buckets | 83.7%/19.4 | 93.4%/16.3 | +--------------------------+--------------------+--------------------+ | 8192 nodes, 8192 buckets | 49.5%/11.4 | 60.3%/7.4 | +--------------------------+--------------------+--------------------+ 2. avc_search_node latency (total latency of hash operation and table lookup) +--------------------------+-----------------------------------------+ | | latency of function avc_search_node | | +--------------------+--------------------+ | | no-patch | with-patch | +--------------------------+--------------------+--------------------+ | 512 nodes, 512 buckets | 87ns | 84ns | +--------------------------+--------------------+--------------------+ | 1024 nodes, 512 buckets | 97ns | 96ns | +--------------------------+--------------------+--------------------+ | 2048 nodes, 512 buckets | 118ns | 113ns | +--------------------------+--------------------+--------------------+ | 8192 nodes, 8192 buckets | 106ns | 99ns | +--------------------------+--------------------+--------------------+ Although MurmurHash3 has higher overhead than the bitwise operations in the original algorithm, the data shows that the MurmurHash3 achieves better distribution, reducing average lookup time. Consequently, the total latency of hashing and table lookup is lower than before. Signed-off-by: Hongru Zhang <zhanghongru@xiaomi.com> [PM: whitespace fixes] Signed-off-by: Paul Moore <paul@paul-moore.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.