From: Andrew Morton <akpm@osdl.org>
To: insecure@mail.od.ua
Cc: jgarzik@pobox.com, lm@bitmover.com, hannal@us.ibm.com,
lse-tech@lists.sourceforge.net, linux-kernel@vger.kernel.org
Subject: Re: Minutes from 10/1 LSE Call
Date: Sat, 4 Oct 2003 22:38:38 -0700 [thread overview]
Message-ID: <20031004223838.338bf4f4.akpm@osdl.org> (raw)
In-Reply-To: <200310030138.34430.insecure@mail.od.ua>
insecure <insecure@mail.od.ua> wrote:
>
> So:
> * we hit a ceiling of ~133 Mb/s, no matter how many disks
> * CPU utilization is 100%, spent mostly in copy_to_user
> * RAM bandwidth is >1Gb/s
>
> These can't be true at once.
True. But bear in mind that the data crosses the memory busses up to three
times: disk to pagecache, pagecache to CPU, CPU to user memory.
So top speed may be as little as 300 MB/sec.
next prev parent reply other threads:[~2003-10-05 5:37 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-10-01 19:19 Minutes from 10/1 LSE Call Hanna Linder
2003-10-01 23:29 ` Andrew Morton
2003-10-01 23:38 ` Larry McVoy
2003-10-02 0:23 ` Jeff Garzik
2003-10-02 18:56 ` insecure
2003-10-02 19:10 ` Jeff Garzik
2003-10-02 22:38 ` insecure
2003-10-02 22:45 ` Hanna Linder
2003-10-05 5:38 ` Andrew Morton [this message]
2003-10-02 19:21 ` [Lse-tech] " Steven Pratt
2003-10-02 19:36 ` Andrew Morton
2003-10-03 19:33 ` Steven Pratt
2003-10-03 20:13 ` Andrew Morton
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