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Date:   Wed, 15 Apr 2020 00:25:12 +0200
From:   Peter Zijlstra <peterz@infradead.org>
To:     Steven Rostedt <rostedt@goodmis.org>
Cc:     Matt Helsley <mhelsley@vmware.com>,
        Julien Thierry <jthierry@redhat.com>,
        linux-kernel@vger.kernel.org, Josh Poimboeuf <jpoimboe@redhat.com>,
        Ingo Molnar <mingo@redhat.com>, Miroslav Benes <mbenes@suse.cz>
Subject: Re: [RFC][PATCH 00/36] objtool: Make recordmcount a subcommand
Message-ID: <20200414222512.GX20730@hirez.programming.kicks-ass.net>
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On Tue, Apr 14, 2020 at 05:47:02PM -0400, Steven Rostedt wrote:
> On Tue, 14 Apr 2020 23:17:54 +0200
> Peter Zijlstra <peterz@infradead.org> wrote:
> 
> > > Do we want that? Matters how long that takes.  
> > 
> > We do want that, however it is conditional on CONFIG_DEBUG_ENTRY and
> > does some rather specific validation. On a defconfig based kernel it
> > takes ~2.5 seconds, significantly more an an allyesconfig.
> 
> Is that timed on your laptop, or on the monster machine you normally do your
> builds on?
> 
> 2.5 seconds for you may be 2.5 minutes for others! ;-)

Final link pass, and objtool, is single threaded, the ~2.5s were on an
old-ish 2.8GHz part, ie, most laptops are faster today.

The machine has a few more cores than laptops have, so total build time
is still managable, unlike laptops. Also, it being a server part, it
suffers less thermal issues.