It definitely (obviously?) wasn't me. I had introduced Brendan to DTrace in 2004 (over e-mail) when I discovered his earlier psio work[0] (which was based on TNF, a tracing facility that predated DTrace that was better than nothing -- but not by much). I knew that he was going to be very excited to learn about DTrace, and it wasn't long before he was delighting us with some really creative scripts. (His shellsnoop.d[1], in particular, really got people's attention as to what what could do with DTrace!)

While he and I had corresponded a bunch, ironically the first time I met Brendan was in 2005, it was in Sydney, and I was on a tour of Australia talking about Solaris 10 -- but it followed this incident by several months (if I recall correctly). I was excited to meet Brendan, and he was excited to meet me -- especially so after his poor experience several months prior!

[0] http://www.brendangregg.com/psio.html

[1] http://www.brendangregg.com/DTrace/shellsnoop.d

Given that Brenden and Bryan worked together closely and seemed to be very fond of each other; and the article mentions that "the VIP may not have known" I think it's safe to assume it was not Bryan.

As if it had been Bryan, Brenden would have been more sure.

To the extent that the two of them have disagreed about things, they don't seem to have any issue saying so publicly, referring to the other by name: https://news.ycombinator.com/item?id=16382456

It feels like Cantrill being a creator of DTrace earns at least the credibility to be called a 'DTrace expert' without quotation marks.

Brendan already replied to another comment saying he doesn't remember the VIP's name.