Date: Mon, 7 Dec 1998 11:12:06 +0100 From: Martin Cracauer <cracauer@cons.org> To: Brett Glass <brett@lariat.org>, chat@FreeBSD.ORG Subject: Re: Question regarding Linux emulation Message-ID: <19981207111206.A20322@cons.org> In-Reply-To: <4.1.19981206215315.042becc0@127.0.0.1>; from Brett Glass on Sun, Dec 06, 1998 at 09:53:49PM -0700 References: <4.1.19981206215315.042becc0@127.0.0.1>
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In <4.1.19981206215315.042becc0@127.0.0.1>, Brett Glass wrote: > I was asked these questions this evening, and don't know the answers. > > How much of a speed penalty, if any, is incurred for using Linux emulation > under FreeBSD compared to running a natively compiled version of the same > program (or, for that matter, running the Linux program under Linux)? How > "thin" is the Linux emulation layer? What calls can be expected to incur a > substantial penalty due to translation of data structures, emulation of > system facilities, etc.? The emulation is mostly just an additional function call and a very short code path to map some table to another (unually the same :-) or to rebuild function arguments, often structs. Even signal delivery code is quite small. Remember that this is only done for system calls and a minimal system call - emulated or not - is so costly in itself that this little extra CPU stuff is unnoticeable. Martin -- %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Martin Cracauer <cracauer@cons.org> http://www.cons.org/cracauer BSD User Group Hamburg, Germany http://www.bsdhh.org/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-chat" in the body of the message
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