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Date:      Thu, 6 Feb 2003 08:50:49 -0800
From:      Arun Sharma <arun@sharma-home.net>
To:        John Baldwin <jhb@FreeBSD.org>
Cc:        smp@freebsd.org, freebsd-gnats-submit@FreeBSD.org
Subject:   Re: kern/18524: The current kernel doesn't keep stats on a per c
Message-ID:  <20030206165049.GA11373@sharma-home.net>
In-Reply-To: <XFMail.20030206111315.jhb@FreeBSD.org>
References:  <3E420FBA.90504@sharma-home.net> <XFMail.20030206111315.jhb@FreeBSD.org>

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On Thu, Feb 06, 2003 at 11:13:15AM -0500, John Baldwin wrote:
> > and submit a new patch:
> > 
> > http://www.sharma-home.net/~adsharma/misc/pcpu-cptime.patch
> 
> [...]
>
> Why not stick the cp_time stuff in struct pcpu instead of using an
> array?

The new patch _is_ putting cp_time in struct pcpu. The old patch in the PR
predates struct pcpu.

I also chose to leave the existing cp_time alone. One could argue that a user
level tool could sum up the pcpu cp_times to derive the cp_time and
the kernel can avoid dirtying an extra cache line. If people feel
strongly about it, I can skip touching cp_time in the SMP case. It's a
choice between compatibility with UP vs performance.

	-Arun

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