Date: Sat, 19 Jul 2003 07:58:01 +0800 From: "David Xu" <davidxu@freebsd.org> To: <deischen@freebsd.org>, "Marcel Moolenaar" <marcel@xcllnt.net> Cc: Julian Elischer <julian@elischer.org> Subject: Re: Rearranging kse mailbox Message-ID: <005201c34d88$6d531bc0$0701a8c0@tiger> References: <Pine.GSO.4.10.10307181835080.18163-100000@pcnet5.pcnet.com>
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----- Original Message -----=20 From: "Daniel Eischen" <eischen@vigrid.com> To: "Marcel Moolenaar" <marcel@xcllnt.net> Cc: <threads@freebsd.org>; "Julian Elischer" <julian@elischer.org> Sent: Saturday, July 19, 2003 6:40 AM Subject: Re: Rearranging kse mailbox > On Fri, 18 Jul 2003, Marcel Moolenaar wrote: >=20 > > On Fri, Jul 18, 2003 at 03:08:40PM -0700, Julian Elischer wrote: > > >=20 > > > the ia64 requires that the thread pointer points to=20 > > > aome location that is 16 bytes long, the first 8 bytes > > > of which is a pointer to the TLS Dynamic thread vector, and the = 2nd 8 > > > bytes is application specific, but in practice, must be a pointer = to > > > the Thread's or KSE's mailbox (I guess KSE to be similar to the = others.) > > >=20 > > > ia32 requires just that the thread control info pointed to by %gs > > > SOMEWHERE contains a pointer to the dtv (where SOMEWHERE is a = known > > > offset). (In our case the offset would be 0) > > >=20 > > > This means that for the UTS to find the active thread under ia64 > > > takes an extra level of indirection. (node neither of these > > > affect upcalls as teh UTS upcall target function has the mailbox = as an > > > argument and can access it independently of %gs or the tp. > > >=20 > > > Am I right that "variant 2" (as seen in the ia32 case) > > > applies to allarchitectures other than ia64? > >=20 > > That is what I need to find out. If the runtime specification has > > a register dedicated for TLS, like on ia64, it will likely behave > > more like ia64 than ia32. I think the amd64 runtime is new enough > > for it to be like ia64. >=20 > The amd64 also has a %gs which is used for this. Only the > kernel can set it, though, so I think it needs to be per-KSE. >=20 > > Note that the extra level of indirection on ia64 can be avoided if > > we put the thread control structure at a negative offset from TP. > > The layout would be something like: > >=20 > > -... 0 8 16 ...+ > > [thread structure][DTV pointer][free][static TLS] > > ^ > > TP >=20 > Can we make this work so that we are not limited to > 8192 (or whatever max user LDTs are) threads on i386? >=20 I think giving 8192 system scope thread limit on i386 might be OK. system might freeze before you reach this limit, better to use M:N thread. :-) > --=20 > Dan Eischen >=20 > _______________________________________________ > freebsd-threads@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-threads > To unsubscribe, send any mail to = "freebsd-threads-unsubscribe@freebsd.org"
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