Date: Tue, 20 May 2014 06:36:18 +0300 From: "Sulev-Madis Silber (ketas)" <madis555@hot.ee> To: Winston Smith <smith.winston.101@gmail.com> Cc: freebsd-arm <freebsd-arm@freebsd.org> Subject: Re: BBB MMC / SD detection instability with U-Boot 2014.04 (CPU 1GHz) Message-ID: <537ACDB2.9080808@hot.ee> In-Reply-To: <CADH-AwEYOYmxbP8zBWOXutR9GJDBsYP8uo=yu37fT49rJdhYzg@mail.gmail.com> References: <537A050E.3040804@hot.ee> <537AB550.2090401@hot.ee> <537AB675.1020006@hot.ee> <024F43EF-E299-413E-AE42-2507AEDD0886@bsdimp.com> <CADH-AwEYOYmxbP8zBWOXutR9GJDBsYP8uo=yu37fT49rJdhYzg@mail.gmail.com>
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On 2014-05-20 05:39, Winston Smith wrote: > On Mon, May 19, 2014 at 10:28 PM, Warner Losh <imp@bsdimp.com> wrote: >> Wow! That’s a lot of added 10ms delays… Do we have a theory of the crime >> for why they are needed? Usually they suggest to me that we’re doing something >> wrong (either not checking the right bits in the bridge, having a fixed retry count >> rather than a timed limit and having some bridges fail more slowly than others >> so the delays are effecting the same thing). > > It's a good start (since the BBB is really flakey at 1Ghz), but yes, > more delays aren't good! > > For what it's worth, I'm working in parallel with both FreeBSD and > Debian Wheezy images on the BBB, and it is quite apparent that the BBB > running FreeBSD is *much* slower to boot than the BBB running Debian; > which currently boots to the login prompt in about 15 seconds from > power up. FreeBSD has a 15-20 second delay just to detect the eMMC, > let alone everything else. > > Comparatively, my x64 FreeBSD VM boots much more quickly than my Ubuntu x64 VM. > > -W. > "really flakey" sounds like "unstable, panics 1000 times a day". I don't see any of that here (as of 11.0-CURRENT r266442). Boot, hmm... yea, 1min (just measured) to fully boot up and connect to server (I'm using ethernet, DHCP, loader boot delay = 3, huge Perl program) might be too slow if you have some embedded system which constantly loses power or something... I haven't tried to do any boot time optimizations yet. Compress kernel? Compress userland? Execute something in parallel on init (NOTE: *DON'T* even think about porting Linux init replacements here)? Use rescue-like static binary? Heavily customize / patch kernel? Use own init? Use rootfs inside kernel? Actually I guess many people might think like me... "HELL, optimizing boot time of 1min?! I have more important tasks to do than this".
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