On Mon, Jan 20, 2020 at 1:38 AM Bohdan Khomutskyi <bkhomuts@xxxxxxxxxx> wrote: > > In my previous message, I mentioned that CPU is underutilized during installation. I haven't investigated further why, but I suspect it's due to the inefficiency caused by the usage of the loop device and/or inefficiency in the rsync itself. Could this be read amplification? This paper on erofs suggests read amplification can be a significant side effect with squashfs. It could be exacerbated with random reads, and I expect it gets worse with larger block size. That's probably mitigated with unsquashfs. Specifically page 4, 2nd paragraph. https://www.usenix.org/system/files/atc19-gao.pdf This also makes me wonder about the memory consumption effect of a 1M block size, especially for Fedora ARM where it looks like Raspberry Pi 2B Most of the ARM images are raw.xz but some are bootable ISOs, dvd and netinstall. And those contain a squashfs sysroot. Even if there's no out of memory problem, it could result in paging. All ISOs setup swap-on-ZRAM these days, lives, DVD, and netinstall. I think the ARM case needs testing before committing to 1M block size across all ISOs, or implementing changes in Fedora release engineering. -- Chris Murphy _______________________________________________ devel mailing list -- devel@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe send an email to devel-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/devel@xxxxxxxxxxxxxxxxxxxxxxx
