docs/73429: [patch] Update Handbook, Chapter 8, kernel configuration

[Joel Dahl]

The following reply was made to PR docs/73429; it has been noted by GNATS.

From: Joel Dahl <joel at automatvapen.se>
To: John Baldwin <jhb at FreeBSD.org>
Cc: FreeBSD-gnats-submit at FreeBSD.org
Subject: Re: docs/73429: [patch] Update Handbook, Chapter 8, kernel
	configuration
Date: Wed, 03 Nov 2004 10:46:49 +0100

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 On Tue, 2004-11-02 at 22:02, John Baldwin wrote:
 > Only note I have (patch looks great!) is that instead of removing SMP, you 
 > probably want to say that 'options SMP' should be added to include support 
 > for multiple processors.  Note that SMP is present in GENERIC on other 
 > architectures such as Alpha and sparc64.  There is also an 'SMP' kernel 
 > config for i386 and amd64.
 
 I've attached an updated patch that includes your suggestion, and I've
 improved the description of ADAPTIVE_GIANT. Thanks.
 
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 --- chapter.sgml	Sun Oct 31 09:06:48 2004
 +++ new.chapter.sgml	Wed Nov  3 10:26:04 2004
 @@ -893,19 +893,28 @@
  
      <programlisting>options          ADAPTIVE_GIANT    # Giant mutex is adaptive.</programlisting>
  
 -    <para>This option causes Giant to be included in the set of mutexes
 -      adaptively spun on.</para>
 +    <para>Giant is the name of a mutual exclusion mechanism (a sleep mutex)
 +      that protects a large set of kernel resources.  Today, this is an
 +      unacceptable performance bottleneck which is actively beeing replaced
 +      with locks that protect individual resources.  The
 +      <literal>ADAPTIVE_GIANT</literal> option causes Giant to be included
 +      in the set of mutexes adaptively spun on.  That is, when a thread
 +      wants to lock the Giant mutex, but it is already locked by a thread
 +      on another CPU, the first thread will keep running and wait for the
 +      lock to be released.  Normally, the thread would instead go back to
 +      sleep and wait for its next chance to run.  If you are not sure,
 +      leave this in.</para>
  
      <indexterm>
        <primary>kernel options</primary>
        <secondary>SMP</secondary>
      </indexterm>
 -    <programlisting># To make an SMP kernel, the next two are needed
 -options         SMP                # Symmetric MultiProcessor Kernel
 -device          apic               # I/O APIC</programlisting>
 +    <programlisting>device          apic               # I/O APIC</programlisting>
  
 -    <para>The above are both required for SMP support, and can also be
 -      safely enabled on uniprocessor systems.</para>
 +    <para>The apic device enables the use of I/O APIC for interrupt
 +      delivery.  The apic device can be used in both UP and SMP kernels, but
 +      is required for SMP kernels.  Add <literal>options SMP</literal> to
 +      include support for multiple processors.</para>
  
      <programlisting>device          isa</programlisting>
  
 @@ -1026,6 +1035,7 @@
  device          asr        # DPT SmartRAID V, VI and Adaptec SCSI RAID
  device          ciss       # Compaq Smart RAID 5*
  device          dpt        # DPT Smartcache III, IV - See NOTES for options
 +device          hptmv      # Highpoint RocketRAID 182x
  device          iir        # Intel Integrated RAID
  device          ips        # IBM (Adaptec) ServeRAID
  device          mly        # Mylex AcceleRAID/eXtremeRAID
 
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