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Rewrite the answer of ``How can I verify which scheduler is in use on a

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running system?'', making sure the kern.quantum vs. kern.sched.quantum
difference between FreeBSD 4.X and 5.X is mentioned.

PR:		docs/74917
Submitted by:	Juho Vuori <juho.vuori@kulma.net>
This commit is contained in:
Giorgos Keramidas 2004-12-16 13:02:04 +00:00
parent fae8f5f4e3
commit 2fb284c96c
Notes: svn2git 2020-12-08 03:00:23 +00:00 
svn path=/head/; revision=23235
1 changed files with 25 additions and 11 deletions
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36
en_US.ISO8859-1/books/faq/book.sgml
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@ -5376,15 +5376,19 @@ device sio5 at isa? port 0x2b8 tty flags 0x501 vector siointr</programlisting>
</question>
<answer>
<para>Just type:
<screen>&prompt.root; <userinput>sysctl kern.quantum</userinput></screen>
If you see
<screen>unknown oid 'kern.quantum'</screen>
it means that the current scheduler is <quote>SCHED_ULE</quote>, however,
if you see
<screen>kern.quantum: 100000</screen>
then the original scheduler <quote>SCHED_4BSD</quote> is the current selection.
</para>
<para>Check if you have a sysctl for the round-robin
scheduling quantum.
This is called <literal>kern.quantum</literal> in pre-5.X
versions of &os; and <literal>kern.sched.quantum</literal>
in &os; 5.X or later.
When the sysctl exists, you will see something like this:
<screen>&prompt.user; sysctl <replaceable>kern.sched.quantum</replaceable>
kern.sched.quantum: 99960</screen>
When it does not exist, &man.sysctl.8; prints a different
message:
<screen>&prompt.user; sysctl <replaceable>kern.sched.quantum</replaceable>
sysctl: unknown oid 'kern.sched.quantum'</screen>
</para>
</answer>
</qandaentry>
@ -5398,10 +5402,20 @@ device sio5 at isa? port 0x2b8 tty flags 0x501 vector siointr</programlisting>
ticks a process can run without being preempted. It is
specific to the 4BSD scheduler, so you can use its
presence or absence to determine which scheduler is in
use.
</para>
use. In &os; 5.X or later <literal>kern.quantum</literal> has
been renamed to <literal>kern.sched.quantum</literal>.</para>
</answer>
</qandaentry>
<qandaentry>
<question id="scheduler-kern-sched-quantum">
<para>What is <literal>kern.sched.quantum</literal>?</para>
</question>
<answer>
<para>See <xref linkend="scheduler-kern-quantum"></para>
</answer>
</qandaentry>
</qandaset>
</chapter>