On Fri, Sep 18, 2020 at 10:49:09AM +0200, Bohdan Khomutskyi wrote: > Hello, > > While working on the change proposal > https://fedoraproject.org/wiki/Changes/OptimizeSquashFS > > I discovered that several kernel configuration options are set sub-optimally > in Fedora. In RHEL 8, the optimal configuration is used. > If we set those options to match RHEL 8, a performance improvement could be > achieved while reading the SquashFS filesystem. > > Below you can see an excerpt from the configuration help: Would you be willing to submit a merge request with these changes for Fedora? Then we can have a discussion and review. Cheers, Don > > Set in RHEL 8: > > SQUASHFS_FILE_DIRECT >     Directly decompress file data into the page cache. >     Doing so can significantly improve performance because >     it eliminates a memcpy and it also removes the lock contention >     on the single buffer. > > SQUASHFS_DECOMP_MULTI_PERCPU >     By default Squashfs uses a single decompressor but it gives >     poor performance on parallel I/O workloads when using multiple CPU >     machines due to waiting on decompressor availability. > >     This decompressor implementation uses a maximum of one >     decompressor per core. It uses percpu variables to ensure >     decompression is load-balanced across the cores. > > Set in Fedora: > SQUASHFS_DECOMP_SINGLE >     Traditionally Squashfs has used single-threaded decompression. >     Only one block (data or metadata) can be decompressed at any >     one time. This limits CPU and memory usage to a minimum. > > SQUASHFS_FILE_CACHE >     Decompress file data into an intermediate buffer and then >     memcopy it into the page cache. > > The SquashFS filesystem is used on installation medium. So making the change > I propose should improve the user experience during installation. It should > also improve the user experience while booting from Fedora Live image. > > Kind regards, > > -- > Bohdan Khomutskyi > Software engineer > Red Hat > _______________________________________________ > kernel mailing list -- kernel@xxxxxxxxxxxxxxxxxxxxxxx > To unsubscribe send an email to kernel-leave@xxxxxxxxxxxxxxxxxxxxxxx > Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/ > List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines > List Archives: https://lists.fedoraproject.org/archives/list/kernel@xxxxxxxxxxxxxxxxxxxxxxx _______________________________________________ kernel mailing list -- kernel@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe send an email to kernel-leave@xxxxxxxxxxxxxxxxxxxxxxx Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/ List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/kernel@xxxxxxxxxxxxxxxxxxxxxxx
