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Pan Deng
e249056c91
When running syscall pread in a high core count system, f_ref contends with the reading of f_mode, f_op, f_mapping, f_inode, f_flags in the same cache line. This change places f_ref to the 3rd cache line where fields are not updated as frequently as the 1st cache line, and the contention is grealy reduced according to tests. In addition, the size of file object is kept in 3 cache lines. This change has been tested with rocksdb benchmark readwhilewriting case in 1 socket 64 physical core 128 logical core baremetal machine, with build config CONFIG_RANDSTRUCT_NONE=y Command: ./db_bench --benchmarks="readwhilewriting" --threads $cnt --duration 60 The throughput(ops/s) is improved up to ~21%. ===== thread baseline compare 16 100% +1.3% 32 100% +2.2% 64 100% +7.2% 128 100% +20.9% It was also tested with UnixBench: syscall, fsbuffer, fstime, fsdisk cases that has been used for file struct layout tuning, no regression was observed. Signed-off-by: Pan Deng <pan.deng@intel.com> Link: https://lore.kernel.org/r/20250228020059.3023375-1-pan.deng@intel.com Tested-by: Lipeng Zhu <lipeng.zhu@intel.com> Reviewed-by: Tianyou Li <tianyou.li@intel.com> Reviewed-by: Tim Chen <tim.c.chen@linux.intel.com> Signed-off-by: Christian Brauner <brauner@kernel.org>
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.