Date: Mon, 11 Jun 2012 18:59:21 -0400 From: Mark Saad <nonesuch@longcount.org> To: Brandon Falk <bfalk_bsd@brandonfa.lk> Cc: "freebsd-hackers@freebsd.org" <freebsd-hackers@freebsd.org> Subject: Re: FreeBSD Boot Times Message-ID: <972AB73F-A761-47E2-A8A3-42C85FDBEE72@longcount.org> In-Reply-To: <4FD66F7E.2060404@brandonfa.lk> References: <4FD66F7E.2060404@brandonfa.lk>
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On Jun 11, 2012, at 6:21 PM, Brandon Falk <bfalk_bsd@brandonfa.lk> wrote: > Greetings, >=20 > I was just wondering what it is that FreeBSD does that makes it take so lo= ng to boot. Booting into Ubuntu minimal or my own custom Linux distro, liter= ally takes 0.5-2 seconds to boot up to shell, where FreeBSD takes about 10-2= 0 seconds. I'm not sure if anything could be parallelized in the boot proces= s, but Linux somehow manages to do it. The Ubuntu install I do pretty much c= onsists of a shell and developers tools, but it still has a generic kernel. T= here must be some sort of polling done in the FreeBSD boot process that coul= d be parallelized or eliminated. >=20 > Anyone have any suggestions? >=20 > Note: This isn't really an issue, moreso a curiosity. >=20 > -Brandon > _____________________________________________ In amd64 builds the system checks it's ram twice . Early in the boot phase u= sing a slower method , and latter using a faster SMAP method. In 9.0-RELEASE= you can disable the early men check via a loader tunable , here is a snip i= t from the release notes on 9.0 . It should also be mfc'd to 7, and 8 stable= .=20 [amd64, i386, pc98] A loader(8) tunable hw.memtest.tests has been added. Thi= s controls whether to perform memory testing at boot time or not. The defaul= t value is 1 (perform a memory test).[r224516] The next it is switch to a modular kernel this speeds up boot times be omit= ting kernel items you do not need, you can also do this via with a static ke= rnel by removing / disabling unused options . Look at the Archives for ha ha= ckers there is a ton of info on this.=20 Most of the rest of the boot up time is via init / rc'ng starting an config= uring things . Right now this is not parallel-ized out the box . Pc-bsd has s= omething called fastboot ? I am am not sure how it works but it improves loa= d time in their setups . See http://lists.pcbsd.org/pipermail/testing/2012-J= anuary/006358.html Other then that, there are some other things being developed check the Free= BSD wiki for a rc.ng management daemon frs or fsr ?=20 --- Mark saad | mark.saad@longcount.org
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