linux-kernel - Re: [PATCH 2/9] x86, perf: Add support for PEBSv3 profiling

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:	Fri, 8 May 2015 13:59:54 +0200
From:	Andi Kleen <andi@...stfloor.org>
To:	Peter Zijlstra <peterz@...radead.org>
Cc:	Andi Kleen <andi@...stfloor.org>, kan.liang@...el.com,
	eranian@...gle.com, acme@...radead.org,
	linux-kernel@...r.kernel.org, Andi Kleen <ak@...ux.intel.com>
Subject: Re: [PATCH 2/9] x86, perf: Add support for PEBSv3 profiling

> That's wrong. It does not respect perf_event_attr::clock_id.

Ok.

Are we really defaulting to real time now? (CLOCK_REALTIME == 0)
What happens when ntpd is active and lets the time drift? That
sounds very bad for event accuracy.

The clockid patch looks broken to me. At least it should default
to MONOTONIC time, not just the time that happens to be 0 by 
accident.

Also I question we really need that many different kinds of
time stamps.

-Andi

-- 
ak@...ux.intel.com -- Speaking for myself only.
--
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/