From: Larry McVoy <lm@bitmover.com>
To: Thomas Ogrisegg <tom@rhadamanthys.org>
Cc: "David S. Miller" <davem@redhat.com>,
linux-kernel@vger.kernel.org, Larry McVoy <lm@bitmover.com>
Subject: Re: [PATCH] TCP Zero Copy for mmapped files
Date: Thu, 2 Jan 2003 14:28:16 -0800 [thread overview]
Message-ID: <20030102222816.GF2461@work.bitmover.com> (raw)
In-Reply-To: <20030102221210.GA7704@window.dhis.org>
> > 1) Does not handle writes that straddle multiple VMAs
>
> What exactly do you mean? In my test, files larger than a
> page were handled perfectly, as well.
mmap(file1 at location [a,b)
mmap(file2 at location [b,c)
write(sock, a, (size_t)(c - a));
> However, I didn't like the VM waste either, but I believe there
> is no other way.
The VM cost hurts. Badly. Imagine that the network costs ZERO. Then
the map/unmap/vm ops become the dominating term. That's why it is a
fruitless approach, it still has a practical limit which is too low.
--
---
Larry McVoy lm at bitmover.com http://www.bitmover.com/lm
next prev parent reply other threads:[~2003-01-02 22:19 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-12-30 1:09 [PATCH] TCP Zero Copy for mmapped files Thomas Ogrisegg
2002-12-30 1:29 ` Larry McVoy
2003-01-02 6:37 ` David S. Miller
2003-01-02 22:12 ` Thomas Ogrisegg
2003-01-02 22:28 ` Larry McVoy [this message]
2003-01-02 23:20 ` Alan Cox
2003-01-02 23:16 ` David S. Miller
2003-01-03 0:56 ` Alan Cox
2003-01-03 2:40 ` David S. Miller
2003-01-03 2:41 ` Linus Torvalds
2003-01-02 23:13 ` David S. Miller
2003-01-03 0:45 ` Thomas Ogrisegg
2003-01-03 1:01 ` Larry McVoy
2003-01-03 1:59 ` Alan Cox
2003-01-06 14:36 ` Gianni Tedesco
2003-01-06 23:29 ` David S. Miller
2003-01-03 1:56 ` Alan Cox
2003-01-03 1:27 ` Larry McVoy
2003-01-03 2:42 ` David S. Miller
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