linux-kernel - Re: [RFC PATCH v2 3/5] futex: Throughput-optimized (TO) futexes

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 for Android: free password hash cracker in your pocket

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

Message-ID: <20160922132347.GX5012@twins.programming.kicks-ass.net>
Date:   Thu, 22 Sep 2016 15:23:47 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     Waiman Long <Waiman.Long@....com>
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...nel.org>,
        Jonathan Corbet <corbet@....net>, linux-kernel@...r.kernel.org,
        linux-doc@...r.kernel.org, Davidlohr Bueso <dave@...olabs.net>,
        Jason Low <jason.low2@....com>,
        Scott J Norton <scott.norton@....com>,
        Douglas Hatch <doug.hatch@....com>
Subject: Re: [RFC PATCH v2 3/5] futex: Throughput-optimized (TO) futexes

On Tue, Sep 20, 2016 at 09:42:41AM -0400, Waiman Long wrote:
> +/*
> + * Spinning threshold before enabling lock handoff.
> + * Each sleep will decrement the threshold by 1/32 of the start value.
> + */
> +#define TO_SPIN_THRESHOLD	(1 << 13)
> +#define TO_SLEEP_DECREMENT	(TO_SPIN_THRESHOLD/32)

Argh, we should really get rid of those stupid numbers. Wasn't there a
patch set working on implementing paravirt functions that would make all
this fixable in a sane way?