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Mainline Linux tree for various devices, only for fun :)
610125ab1e
When running a "create millions inodes in a directory" test recently, I noticed we were spending a huge amount of time converting freespace block headers from disk format to in-memory format: 31.47% [kernel] [k] xfs_dir2_node_addname 17.86% [kernel] [k] xfs_dir3_free_hdr_from_disk 3.55% [kernel] [k] xfs_dir3_free_bests_p We shouldn't be hitting the best free block scanning code so hard when doing sequential directory creates, and it turns out there's a highly suboptimal loop searching the the best free array in the freespace block - it decodes the block header before checking each entry inside a loop, instead of decoding the header once before running the entry search loop. This makes a massive difference to create rates. Profile now looks like this: 13.15% [kernel] [k] xfs_dir2_node_addname 3.52% [kernel] [k] xfs_dir3_leaf_check_int 3.11% [kernel] [k] xfs_log_commit_cil And the wall time/average file create rate differences are just as stark: create time(sec) / rate (files/s) File count vanilla patched 10k 0.41 / 24.3k 0.42 / 23.8k 20k 0.74 / 27.0k 0.76 / 26.3k 100k 3.81 / 26.4k 3.47 / 28.8k 200k 8.58 / 23.3k 7.19 / 27.8k 1M 85.69 / 11.7k 48.53 / 20.6k 2M 280.31 / 7.1k 130.14 / 15.3k The larger the directory, the bigger the performance improvement. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> |
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| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
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 Restructured Text 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.