Date: Sat, 13 Apr 2019 11:39:18 -0700 From: Mark Millard <marklmi@yahoo.com> To: Dennis Clarke <dclarke@blastwave.org> Cc: freebsd-ppc@freebsd.org Subject: Re: Patches to allow usefdt mode that works on a 2 socket PowerMac3, 6 example too --and makes more work on 2-socket/1-core-each PowerMac11, 2 Message-ID: <55E83F50-197D-43C7-B4D6-E69A5AEC2630@yahoo.com> In-Reply-To: <A4E361A0-4C6C-4E37-BB04-AB52094F4206@yahoo.com> References: <988F644F-D5E7-4FB4-AAB3-A72E9DA88CE6@yahoo.com> <af38e008-d9f9-9364-56c5-56387cbcf95d@blastwave.org> <465DBF40-EEF5-4D4A-95F6-DF17EB5B130B@yahoo.com> <5aecd21e-e53c-f14c-0bdc-8732fa88fed6@blastwave.org> <A4E361A0-4C6C-4E37-BB04-AB52094F4206@yahoo.com>
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[My adjustment to fdt_add_subnode_namelen was inept.] On 2019-Apr-12, at 16:17, Mark Millard <marklmi at yahoo.com> wrote: > On 2019-Apr-12, at 14:20, Dennis Clarke <dclarke a t blastwave.org> wrote: > >> On 4/12/19 4:51 PM, Mark Millard wrote: >>> On 2019-Apr-12, at 13:13, Dennis Clarke <dclarke at blastwave.org> wrote: >>>> On 4/12/19 3:19 PM, Mark Millard via freebsd-ppc wrote: >> . >> . >> . >>>> >>>> Would you be so kind as to paste all this into : >>>> >>>> https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=233863 >>>> >>>> Really I would like to run some tests and follow up in the bug reports. >>> Okay I'll paste them in as attachments. But be warned: >> >> Fair warning received loud and clear :-) >> >>> The 2 files do not deal with threads being stuck sleeping >>> (and, so, the fans going) or other such. The stuck-sleeping >>> problem happens for both multi-socket G5's and multi-socket >>> G4's. (I do not have access to single-socket multi-core >>> powerpc64 or powerpc machines to test.) >> >> I have multiple G5 type boxen and will try them out. At least try >> to. >> >>> So do not expect too much from these patches: They address >>> some necessary issues but are not sufficient for everything. >>> >> >> Of course. No problem. >> >> >>> These patches for the openfirmware->fdt translation are >>> closer to being reasonable for FreeBSD official use >>> than my highly context-specific stuck-sleeping patches for >>> usefdt mode. >> >> Well to be frank we know this is for mac g5 hardware and thus having >> them working at all in any fashion is better than the current situation. >> Apple made a ton of them and they are dirt cheap and available as >> opposed to the IBM Power situation which is expensive and just in >> datacenters. > > > I have added another attachment with patches for having hang-ups > at AP startup happen less often. These are in AIM-specific code > and so has less of a chance of causing other contexts problems. > They are also powerpc64 specific. Again, the patches are > investigatory and not in a form for direct check-in to FreeBSD. > > This pair of patches narrows the time period over which threads > from the stages: > > SI_SUB_KTHREAD_INIT = 0xe000000, /* init process*/ > SI_SUB_KTHREAD_PAGE = 0xe400000, /* pageout daemon*/ > SI_SUB_KTHREAD_VM = 0xe800000, /* vm daemon*/ > SI_SUB_KTHREAD_BUF = 0xea00000, /* buffer daemon*/ > SI_SUB_KTHREAD_UPDATE = 0xec00000, /* update daemon*/ > SI_SUB_KTHREAD_IDLE = 0xee00000, /* idle procs*/ > #ifndef EARLY_AP_STARTUP > SI_SUB_SMP = 0xf000000, /* start the APs*/ > #endif > > can conflict with starting an AP via an slb replacement position > picked via expressions like mftb()%n_slbs . It does this by > explicitly picking and setting up a slb slot for its use just > before starting the AP. > > (The AP has to be part way along before it can do its own > automatic-random-slb-slot-replacements from what I can tell.) > > The patches do not remove the race and still do sometimes fail to > prevent getting a hang-up on a AP start. But it greatly decreased > the rate of hangups in my testing. (So it is a good source of > evidence about the original problem.) > > If EARLY_AP_STARTUP was supported and used, the AP startup would > not have hang-up problems from mftb()%n_slbs based slb > replacements for other threads. > > The patches are a hack, rather than a general/complete fix --and > I do not expect to see them in FreeBSD. But they do help set up > a better context for investigating other things. The disabling of blocking duplicate paths in fdt_add_subnode_namelen was done incorrectly. I'll replace the attachment after building and testing. I think this is the explanation for the PowerMac11,2 shutdown -r or -p problems. The code should have just disabled the return, more like: if (offset >= 0) #if 0 // Some Macintoshes have identical package-to-pathname results for // multiple nodes of the same type and unit under the parent node. // Avoid blocking this for fdt. return -FDT_ERR_EXISTS; #else ; #endif else if (offset != -FDT_ERR_NOTFOUND) return offset; Instead the messed up change did the "return offset;" and so did not do the addition of the node, instead returning the pre-existing one to be manipulated. === Mark Millard marklmi at yahoo.com ( dsl-only.net went away in early 2018-Mar)
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