On Fri, Oct 02, 2020 at 04:12:46PM +0200, Bohdan Khomutskyi wrote: > Hello Don, > > I filed a new merge request for this suggestion. It is now open at the > following URI: > https://gitlab.com/cki-project/kernel-ark/-/merge_requests/673
Perfect. Thanks! I see Justin already accepted it! Cheers, Don > > Kind regards, > > On 29/09/2020 16:34, Don Zickus wrote: > > 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 > > > ÃÂ ÃÂ ÃÂ ÃÂ Directly decompress file data into the page cache. > > > ÃÂ ÃÂ ÃÂ ÃÂ Doing so can significantly improve performance because > > > ÃÂ ÃÂ ÃÂ ÃÂ it eliminates a memcpy and it also removes the lock > > > contention > > > ÃÂ ÃÂ ÃÂ ÃÂ on the single buffer. > > > > > > SQUASHFS_DECOMP_MULTI_PERCPU > > > ÃÂ ÃÂ ÃÂ ÃÂ By default Squashfs uses a single decompressor but it > > > gives > > > ÃÂ ÃÂ ÃÂ ÃÂ poor performance on parallel I/O workloads when using > > > multiple CPU > > > ÃÂ ÃÂ ÃÂ ÃÂ machines due to waiting on decompressor availability. > > > > > > ÃÂ ÃÂ ÃÂ ÃÂ This decompressor implementation uses a maximum of one > > > ÃÂ ÃÂ ÃÂ ÃÂ decompressor per core.ÃÂ It uses percpu variables to > > > ensure > > > ÃÂ ÃÂ ÃÂ ÃÂ decompression is load-balanced across the cores. > > > > > > Set in Fedora: > > > SQUASHFS_DECOMP_SINGLE > > > ÃÂ ÃÂ ÃÂ ÃÂ Traditionally Squashfs has used single-threaded > > > decompression. > > > ÃÂ ÃÂ ÃÂ ÃÂ Only one block (data or metadata) can be decompressed > > > at any > > > ÃÂ ÃÂ ÃÂ ÃÂ one time.ÃÂ This limits CPU and memory usage to a > > > minimum. > > > > > > SQUASHFS_FILE_CACHE > > > ÃÂ ÃÂ ÃÂ ÃÂ Decompress file data into an intermediate buffer and > > > then > > > ÃÂ ÃÂ ÃÂ ÃÂ 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 -- [email protected] > > > To unsubscribe send an email to [email protected] > > > 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/[email protected] > > -- > Bohdan Khomutskyi > Software engineer > Red Hat > _______________________________________________ kernel mailing list -- [email protected] To unsubscribe send an email to [email protected] 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/[email protected]
