Date: Mon, 22 Jun 2009 09:31:27 -0700 From: Sam Leffler <sam@freebsd.org> To: Jeff Roberson <jroberson@jroberson.net> Cc: arch@freebsd.org, Peter Grehan <grehan@freebsd.org>, Marius Strobl <marius@alchemy.franken.de> Subject: Re: Dynamic pcpu, arm, mips, powerpc, sun, etc. help needed Message-ID: <4A3FB1DF.80006@freebsd.org> In-Reply-To: <alpine.BSF.2.00.0906211406300.998@desktop> References: <alpine.BSF.2.00.0906032050220.981@desktop> <20090609201127.GA50903@alchemy.franken.de> <4A2F1148.9090706@freebsd.org> <alpine.BSF.2.00.0906171231540.1025@desktop> <20090621140312.GC71667@alchemy.franken.de> <alpine.BSF.2.00.0906211406300.998@desktop>
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Jeff Roberson wrote: > On Sun, 21 Jun 2009, Marius Strobl wrote: > >> On Wed, Jun 17, 2009 at 12:55:52PM -1000, Jeff Roberson wrote: >>> >>> On Tue, 9 Jun 2009, Peter Grehan wrote: >>> >>>>> As for sparc64 allocating the storage for the dynamic area >>>>> from end probably isn't a good idea as the pmap code assumes >>>>> that the range from KERNBASE to end is covered by the pages >>>>> allocated by and locked into the TLB for the kernel by the >>>>> loader >>>> >>>> Ditto for ppc. It's possible to get the additional space from >>>> within or >>>> after return from pmap_bootstrap() (like thread0's kstack, or the >>>> msgbuf). >>> >>> http://people.freebsd.org/~jeff/dpcpu.diff >>> >>> I have updated this patch based on feedback relating to various >>> architectures md code. I tried to model most architectures after the >>> way >>> msgbuf memory was taken. I have no capacity to test anything other than >>> i386 and amd64. ARM is reported to work with one minor diff. Apparently >>> sparc64 worked with the earlier diff but this should be cleaner. If >>> anyone can report back on sparc64, mips, or powerpc, I'd appreciate it. >>> >> >> The earlier patch worked on sparc64 as long as the kernel >> happened to leave enough room in the last 4MB page allocated >> for it. >> The new version unfortunately doesn't compile on sparc64 as >> pmap_bootstrap_alloc() is static to its pmap.c (I think it >> should also stay that way). Also the memory allocated with >> it isn't safe to be used before we've taken over the trap >> table. A kernel built with the sparc64 bits replaced with >> the following patch boots fine: >> http://people.freebsd.org/~marius/sparc64_dpcpu.diff >> Do you have some simple test case for DPCPU which can be >> used to verify that it actually works? > > Thanks very much Marius. I have updated the patch at: > > http://people.freebsd.org/~jeff/dpcpu.diff > > I intend to commit this, minus the kern_synch.c diff tomorrow. There > was an id in the previous patch that caused each area to be accessed > as it was added but you'd have to have done a 'show pcpu' in ddb after > boot to access the area. I added a counter in kern_synch.c as a better > test. > > new in this diff: > > 1) I made each access cheaper by one instruction by making the > pc_dynamic pointer relative to the start of the percpu area. > > 2) I added two helper functions for sysctl ints and quads that can be > used for stats. See the temporary kern_synch.c diff for an example. > > 3) sparc64/sun4v by marius > > 4) ia64 fixes suggested by marcel. Does not compile on !SMP systems (s/dpcpu_ptr/dcpu_off/ in sysctl_dpcpu_quad). Sam
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