linux-kernel - Re: [PATCH 1/2] tools, perf: Add a precise event qualifier v2

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Thu, 25 Jul 2013 23:58:09 -0400 (EDT)
From:	Vince Weaver <vince@...ter.net>
To:	Andi Kleen <andi@...stfloor.org>
cc:	Andi Kleen <ak@...ux.intel.com>, acme@...radead.org,
	mingo@...nel.org, linux-kernel@...r.kernel.org,
	Peter Zijlstra <peterz@...radead.org>,
	Stephane Eranian <eranian@...gle.com>,
	torvalds@...ux-foundation.org, trinity@...r.kernel.org
Subject: Re: [PATCH 1/2] tools, perf: Add a precise event qualifier v2

On Wed, 24 Jul 2013, Andi Kleen wrote:

> Sorry I meant flags as an alias of "the 64bits currently occupied by the
> bitfield". Perhaps the name choice was not very good.
> 
> "flags_bitfield" ?
> 
> So the tool would only need to know that, not every bit.
> 
> In theory it could be also generalized as a byte offset to perf_event,
> but that may be overengineered.

I somehow doubt this would be acceptable.  If it were, we could have had a 
somewhat better interface by just having the event fields be a list of 
values without involving format/* at all, something like

   config=0x58034;config1=0x20;precise_ip=0x4

For whatever reason things have to be human readable, and I don't think
just having an opaque 64-bit "flags" value will be accepted.  

I'm likely wrong though, I have a very low accuracy rate for predicting 
future perf_event design decisions.

This is all complicated by the intertwined nature of the perf_event ABI 
and the perf tool, and the way that there's at least three or four 
different ways to specify the same event from the perf tool command line.

Vince
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/