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    Thumbs up There is no overall performance drop when you run FreeBSD in Linux compatibility mode


    Well I was going to ask this question, but thought I would pass along the information to those interested. We have to use a Linux RAID manager. Well we don't HAVE to, but the program has some increased functionality that doesn't exist in the FreeBSD version of the software.

    Anyway, I was concerned that enabling Linux compatibility might adversely affect system performance. In that case, I would have wanted to turn the compatibility on as needed.

    Most of my research backs up what most people are saying: FreeBSD won't experience a performance drop, and in many cases, will run Linux programs faster than Linux does.

    The emulation layer is so thin that it doesn't have an inherited performance drop. The emulation layer just adds a few computations to every system call. A system call on a UNIX system is always a costly operation that requires several times the operations the biggest parts of the emulation layer take.
    http://www.cons.org/cracauer/freebsd.html

    I know this is old hat for some of you guys, so if anyone has anything to add or contradict this, feel free!
    Last edited by Ted Striker; February 9th, 2002 at 08:00 PM.
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    Interesting article. Hopefully someone in future can setup some benchmarks and/or tests to substantiate the issue of Linux emulation.

    I believe that the emulation issue may also depend on the type and nature of the application(s) you are running (depending on the system calls and the frequency with with they are made).

    Unfortunately, sometimes the choice of an OS is based on its ability to run/support an application. Many people want to pick a cheaper and faster Intel based alternative to Microsoft to run and manage their business applications reliably.

    The last time I picked Sybase and Oracle database, they ran readily on Linux, but through an emulation layer when using FreeBSD. When folks try to pick an OS, they have to choose between "Linux" and "Linux Emulation" and guess which one they pick ? They are afraid of going through the extra (unknown) effort of supporting such apps on FreeBSD.

    A lot of game-focused newbies also tend to make a similar choice with "Quake" etc. which again does not run natively on FreeBSD to the best of my knowledge.

    So the "thin emulation layer" concept, if indeed true across the board, should really be promoted/advocated by our FreeBSD community!

    Thanks for pointing this article. Best Wishes.
    Last edited by freebsdforums; February 15th, 2002 at 09:49 AM.

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