Date: Mon, 19 May 2014 22:07:52 -0600 From: Warner Losh <imp@bsdimp.com> To: "Sulev-Madis Silber (ketas)" <madis555@hot.ee> Cc: freebsd-arm <freebsd-arm@freebsd.org> Subject: Re: BBB MMC / SD detection instability with U-Boot 2014.04 (CPU 1GHz) Message-ID: <E85AB625-9954-471D-B9D8-B614F9794487@bsdimp.com> In-Reply-To: <537ACDB2.9080808@hot.ee> 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> <537ACDB2.9080808@hot.ee>
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[-- Attachment #1 --] On May 19, 2014, at 9:36 PM, Sulev-Madis Silber (ketas) <madis555@hot.ee> wrote: > 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”. Make MMC faster, and a lot of this will go away. When I was doing Atmel, I got more milage out of optimizing the I/O path for slow boots than I did for just about anything else. Another quick hack: delete all files in /etc/rc.d that aren’t used. Warner [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- Comment: GPGTools - https://gpgtools.org iQIcBAEBCgAGBQJTetUYAAoJEGwc0Sh9sBEASacP/1QMabYYqfMhPsQ0bsMYA9q2 Dkr0JhSeHtp9KeLWMfezjfCYcrhJBJY+VL1RBj50dDXtNyYYXDrUtGL7c1TzhbTp tAXUnVyutwxaD10HSskxA0EVJlPY6wfZxSMdGzT1FI2ZJw1sqzUQEyimwaIWJX4A S/70Ce5SnqSSBsTPwk1d4YHFzd3C7GYHApHQ/NmP5YNgAhAC30h/VY+15HWkM78j K7lUKm9dkbvP+94hOrHoTaq/BuVgXSu1LsthOTzzWa8ZJZHQlddp0kU4deb5DkZM xrW9y2IDopm9LSkBR6cBKYNHouE01nVeO2FLAwf3wVWkdFxS1TLkL5rqcBE1A86F CoJzwI23jXlMqKAd1Bw4ymEnGYTTA3fuUsn9mFUI5PdDGkJakTFp2R/74DQQpxe8 vExAkrOfKUv1U2gp+TyfULuhu4Zhv6anrqpWrCnPo6jyyHFmzlssqydrUTlw4Jtx 2xHzD7kK+ASVNP815+jswtGokQC6onPxiFXKkfWF+ZvuwD0T++BN0c0IJO2Oje7k d0rdPT4JXaptNsJepIH+Rc1tYdQUoqM1EWOjuqLaC4djfZK1IcmQMMf1rM+QyX5V r5p6lY5braH/doSiM2F//hRijPmTAWq6jPwogDDLmtPJ/5c+XPD/08F4bY5ihv// TmRrkfDlQwHJtAnI2eXh =5qoi -----END PGP SIGNATURE-----home | help
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