On Fri, Aug 19, 2016 at 5:27 AM, Konstantin Belousov <kostik...@gmail.com> wrote: > On Fri, Aug 19, 2016 at 09:12:53PM +1000, Bruce Evans wrote: >> On Fri, 19 Aug 2016, Konstantin Belousov wrote: >> >> > On Thu, Aug 18, 2016 at 09:28:57PM -0600, Warner Losh wrote: >> >> On Thu, Aug 18, 2016 at 12:50 AM, Julian Elischer <jul...@freebsd.org> >> >> wrote: >> >>> On 16/08/2016 4:54 AM, John Baldwin wrote: >> >>>> >> >>>> On Monday, August 15, 2016 08:38:02 PM John Baldwin wrote: >> >>>>> ,,, >> >>>>> Log: >> >>>>> Remove the mcd(4) driver for Mitsumi CD-ROM players. >> >>>>> This is a driver for a pre-ATAPI ISA CD-ROM adapter. As noted in >> >>>>> the manpage, this driver is only useful as a backend to cdcontrol to >> >>>>> play audio CDs since it doesn't use DMA, so its data performance is >> >>>>> "abysmal" (and that was true in the mid 90's). >> >>>> >> >>>> No one stepped up to test patches for it either when I last posted >> >>>> patches >> >>>> to >> >>>> convert it from timeout(9) to callout(9). I have a few more drivers >> >>>> that >> >>>> are >> >>>> ... >> >>> >> >>> I would imagine any machine still holding one of these probably has not >> >>> enough memory to run FreeBSD. >> >>> >> >>> would we still run in 2MB? >> >> >> >> With insane levels of tuning, we can run in 32MB userland that can do >> >> things. Even 64MB is tight w/o some tuning. 16MB is almost certainly >> >> right out except for very specialized situations. 2MB? We can't even >> >> load the loader in that :(. Oh, and all these memory configs are only >> >> possible if you tweak the loader's block cache... >> > >> > 32MB is quite usable. Without any tuning, you get slightly less than 10MB >> > for userspace, which is enough to for many things, and plenty if swap is >> > added. >> >> No, 32MB needs lots of needs tuning. -current seems to need about 16MB >> more than just a few months ago when I last discussed this with you. >> My i386 system doesn't have many drivers or a bloated userland (*), >> but it took the following tuning plus my PAE tuning fixes to boot in >> 32MB: >> - disable [l]em1 >> - reduce tx and buffers to 256 for em0. They default to 4096 for em. That >> is something like 8K * 1500 bytes = 12MB for em0 alone. lem[1] wants >> another 12MB. I think this is not all statically allocated, but the >> drivers hang onto that much. >> This now longer works. -current without my PAE tuning fixes hangs mounting >> root or in usb initialization with this tuning and 40MB. -current with my >> PAE tuning fixes hangs similarly with 32MB; with 40MB it boots to the >> start of multiuser but then hangs (it starts 1 getty, then 2 sendmails >> and kills them with "out of swap space") and 1 rpcbind (also killed). I >> don't use swap, but it was needed 20 years ago on a system that actually >> had 32MB of memory. >> >> (*) /bin/sh doing nothing much in -current i386: size 6532K res 1924K >> /bin/sh in my ~5.2 i386: size 864K res 592K >> >> The kernel size is 5.5MB text 370K data 2.2MB bss (lots of bloat in bss >> for debugging and vt). In single user mode, with 40MB to start, there >> is 22116K wired and 2516K free. A few programs can be run in 2516K >> without swap if they have res 592K and not 1924K. >> >> > Note that you cannot boot on such configurations since loader was broken, >> > but if you do manage to jump to kernel, things were fine several months >> > ago. I tested my relatively recent OOM changes on 32MB qemu config. >> >> I have no problems booting such configuratations since I don't use the >> current loader and only use old loader to change the environment to >> set up special configurations like this. I use my version of biosboot >> for boot2. This requires fixing 2 layers of complicated breakage in >> init386(). vm86 is now used before the TSS and PIC resources that it >> uses are initialized, but only in paths that are not normally used >> because they are for memory sizing that is normally done by loader >> :-(. >> >> I normally use my version of biosboot for boot2. I improved its caching >> just a couple of years ago. It was using 9K buffer optimized for 1440K >> floppies. Now it uses a 32K buffer. Booting a 5.5MB kernel takes a >> fraction of a second. Of course I don't use modules, so not many seeks >> are needed. > > Of course I use modules and do not use GENERIC. I just tried: with today > HEAD, and old loader on 32MB VM, I get 11MB free in single-user mode. > Active+inactive is ~4MB, and 1M is eaten by buffers, which is about right > for init+/bin/sh+top idle system.
The situation on x86 must be a lot better than arm. My old Atmel boards with 32MB have < 1MB free when booted to the login prompt (more at single user) and need special tuning to reduce the 5MB of network buffers allocated to be anything approaching useful. Warner _______________________________________________ svn-src-all@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
