From mboxrd@z Thu Jan  1 00:00:00 1970
From: j.neuschaefer@gmx.net (Jonathan =?utf-8?Q?Neusch=C3=A4fer?=)
Date: Fri, 8 Jun 2012 23:48:15 +0200
Subject: is memcpy a system call?
In-Reply-To: <4FD21628.1050800@gmail.com>
References: <4FD21628.1050800@gmail.com>
Message-ID: <20120608214815.GA2711@debian.debian>
To: kernelnewbies@lists.kernelnewbies.org
List-Id: kernelnewbies.lists.kernelnewbies.org

On Sat, Jun 09, 2012 at 12:11:36AM +0900, J.Hwan Kim wrote:
> Hi, everyone
> 
> Is memcpy a system call?
> 
> Thanks in advnace,
> 
> Best Regards,
> J.Hwna Kim

"strace" is a good tool to find out which system calls a program is
doing.

To answer your question, I don't think it makes much sense to implement
memcpy as a syscall, because entering kernel mode is usually relatively
expensive and I can't think of any kernel mode-only memcpy optimizations
(and optimizations are the only reason to do a user space memcpy in
kernel space I can think of).

HTH,
	Jonathan Neusch?fer