Alexander Shishkin <[email protected]> writes: > Now that Intel PT supports more types of trace content than just branch > tracing, it may be useful to allow the user to disable branch tracing > when it is not needed. > > The special case is BDW, where not setting BranchEn is not supported. > > This is slightly trickier than necessary, because up to this moment > the driver has been setting BranchEn automatically and the userspace > assumes as much. Instead of reversing the semantics of BranchEn, we > introduce a 'passthrough' bit, which will forego the default and allow > the user to set BranchEn to their heart's content.
cpu/passthrough=1,branchen=1/ seems far uglier/more complicanted to me than the original cpu/nobranch=1/ Just think how you would explain it to the user in the manpage. -Andi
