On Thu, 2009-06-11 at 07:30 +0100, Metzger, Markus T wrote: > >-----Original Message----- > >From: tip-bot for Ingo Molnar [mailto:mingo@xxxxxxx] > >Sent: Thursday, June 11, 2009 1:37 AM > >To: linux-tip-commits@xxxxxxxxxxxxxxx > >Cc: hpa@xxxxxxxxx; mingo@xxxxxxxxxx; peterz@xxxxxxxxxxxxx; Metzger, Markus T; oleg@xxxxxxxxxx; > >tglx@xxxxxxxxxxxxx; mingo@xxxxxxx > >Subject: [tip:tracing/core] Revert "x86, bts: reenable ptrace branch trace support" > > > >Commit-ID: 511b01bdf64ad8a38414096eab283c7784aebfc4 > >Gitweb: http://git.kernel.org/tip/511b01bdf64ad8a38414096eab283c7784aebfc4 > >Author: Ingo Molnar <mingo@xxxxxxx> > >AuthorDate: Thu, 11 Jun 2009 00:32:00 +0200 > >Committer: Ingo Molnar <mingo@xxxxxxx> > >CommitDate: Thu, 11 Jun 2009 00:32:00 +0200 > > > >Revert "x86, bts: reenable ptrace branch trace support" > > > >This reverts commit 7e0bfad24d85de7cf2202a7b0ce51de11a077b21. > > > >A late objection to the ABI has arrived: > > > > http://lkml.org/lkml/2009/6/10/253 > > I thought that this has been resolved. See for example http://lkml.org/lkml/2009/6/10/257. > > Peters concerns were that Debug Store details are exposed to user space, which is > not the case. Debug Store itself is fully in-kernel and the expectation of a > user-defined buffer can be implemented on top of the Debug Store changes that > Peter expects are needed to support PEBS. > > A user-defined trace buffer size is required to support different usage models. > Some users only need a small amount of trace, whereas others need a big amount. > The interface will have to reflect that in some way. Right, your last email did explain how we could keep per task in-kernel buffers and fill them from the DS and still have them of user-specified size. That would indeed keep the proposed ABI workable, what I'm still not liking is that this buffer is in-kernel, but I guess that might be something for other people to have an opinion on. -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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