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From: Peter Xu <peterx@redhat.com>
To: nsaenzju@redhat.com
Cc: linux-rt-users@vger.kernel.org, williams@redhat.com, jkacur@redhat.com
Subject: Re: [PATCH 2/3] oslat: Add aarch64 support
Date: Fri, 10 Sep 2021 13:00:02 -0400	[thread overview]
Message-ID: <YTuPElzm4lwm+7iT@t490s> (raw)
In-Reply-To: <1f3916ebd3bb9d886dee56404127308a7be8098e.camel@redhat.com>

On Fri, Sep 10, 2021 at 04:27:05PM +0200, nsaenzju@redhat.com wrote:
> My understanding is that can only happen when the expression to right of 'a'
> has no dependencies with t2. And at that stage, do we really care? Well, yes,
> for example if you're measuring how long it took to assign a, which is similar
> to what we do:
> 
> 	workload_fn workload = g.workload->w_fn;
> 	frc(&t1)
> 	workload()
> 	frc(&t2)
> 
> But in that case the compiler is forced to handle the indirect function call
> and IIUC there is little optimization todo, so we're safe without barriers.

Yep.

> 
> That said, I don't feel overly confident about all this, and there is little
> downside to the compiler barriers, so I'll just add them.

Yep, too.

IMHO that's the point (even I know it's trivial and I'm harsh :-D) - we don't
have a reason to drop it if it helps us to make sure there's no surprise.

Thanks,

-- 
Peter Xu


  reply	other threads:[~2021-09-10 17:00 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-08 10:02 [PATCH 1/3] oslat: rename cpu_mhz/cpu_hz to timer_mhz/cpu_hz Nicolas Saenz Julienne
2021-09-08 10:02 ` [PATCH 2/3] oslat: Add aarch64 support Nicolas Saenz Julienne
2021-09-08 18:09   ` Peter Xu
2021-09-09 10:10     ` nsaenzju
2021-09-09 18:03       ` Peter Xu
2021-09-10 12:19         ` nsaenzju
2021-09-10 13:33           ` Peter Xu
2021-09-10 14:27             ` nsaenzju
2021-09-10 17:00               ` Peter Xu [this message]
2021-09-08 10:02 ` [PATCH 3/3] oslat: Allow for arch specific timer frequency measurements Nicolas Saenz Julienne
2021-09-08 18:16   ` Peter Xu
2021-09-09 10:29     ` nsaenzju
2021-09-09 18:04       ` Peter Xu
2021-09-08 14:40 ` [PATCH 1/3] oslat: rename cpu_mhz/cpu_hz to timer_mhz/cpu_hz Peter Xu
2021-09-08 16:30   ` nsaenzju
2021-09-08 17:51     ` Peter Xu
2021-09-09  9:41       ` nsaenzju
2021-09-09 18:05         ` Peter Xu

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