Vale style checks for tuning guide

xml/tuning_systemtap.xml

@@ -30,7 +30,7 @@
   examine the activities of a running Linux system, particularly the kernel,
   in fine detail. &stap; scripts are written in the &stap; scripting
   language, are then compiled to C-code kernel modules and inserted into the
-  kernel. The scripts can be designed to extract, filter and summarize data,
+  kernel. The scripts can be designed to extract, filter, and summarize data,
   thus allowing the diagnosis of complex performance problems or functional
   problems. &stap; provides information similar to the output of tools
   like <command>netstat</command>, <command>ps</command>,
@@ -144,7 +144,7 @@
     to make it easier for users to define events and functions. Tapsets
     provide aliases for functions that users could want to specify as an
     event. Knowing the proper alias is often easier than remembering
-    specific kernel functions that might vary between kernel versions.
+    specific kernel functions that may vary between kernel versions.
    </para>
   </sect2>
 
@@ -208,7 +208,7 @@
     To avoid giving &rootuser; access to users solely to enable them to work
     with &stap;, use one of the following &stap; groups. They are not available
     by default on &productname;, but you can create the groups and modify the
-    access rights accordingly.  Also adjust the permissions of the
+    access rights accordingly. Also adjust the permissions of the
     <command>staprun</command> command if the security implications are
     appropriate for your environment.
    </para>
@@ -274,7 +274,7 @@
      </term>
      <listitem>
       <para>
-       Holds several example &stap; scripts for various purposes.
+       Holds several example &stap; scripts for different purposes.
        Only available if the
        <systemitem class="resource">systemtap-docs</systemitem> package is
        installed.
@@ -461,7 +461,7 @@
 
   <para>
    To get access to the man pages and to a helpful collection of example
-   &stap; scripts for various purposes, additionally install the
+   &stap; scripts for different purposes, additionally install the
    <systemitem class="resource">systemtap-docs</systemitem> package.
   </para>
 
@@ -1240,7 +1240,7 @@ root  4700  4160  0 18:05 ttyS0  00:00:00 grep avahi</screen>
   </para>
 
   <para>
-   Comments can be inserted anywhere in the &stap; script in various
+   Comments can be inserted anywhere in the &stap; script in different
    styles: using either <literal>#</literal>, <literal>/* */</literal>, or
    <literal>//</literal> as marker.
   </para>
@@ -1360,7 +1360,7 @@ root  4700  4160  0 18:05 ttyS0  00:00:00 grep avahi</screen>
     of the specified events occur.
    </para>
    <para>
-    In general, events can be classified into the following categories:
+    The events can be classified into the following categories:
    </para>
    <itemizedlist mark="bullet" spacing="normal">
     <listitem>
@@ -1454,7 +1454,7 @@ probe <replaceable>EVENT</replaceable> {<replaceable>FUNCTION_NAME</replaceable>
      Functions can be defined anywhere in the script. They may take any
     </para>
     <para>
-     One of the functions needed very often was already introduced in
+     One of the functions frequently needed is already introduced in
      <xref linkend="ex-tuning-stap-simple"/>: the <literal>printf</literal>
      function for printing data in a formatted way. When using the
      <literal>printf</literal> function, you can specify how arguments
@@ -1634,8 +1634,7 @@ held(2360) open
       (<literal>%d</literal>).
      </para>
      <para>
-      However, by default, variables are local to the probe they are used
-      in: They are initialized, used and disposed of at each handler
+      However, by default the variables are local to the probe containing them. They are initialized, used, and disposed of at each handler
       evocation. To share variables between probes, declare them global
       anywhere in the script. To do so, use the <literal>global</literal>
       keyword outside of the probes:
@@ -1670,7 +1669,7 @@ probe timer.ms(12345)
      <title>Conditional statements</title>
      <para>
       There are several conditional statements that you can use in
-      &stap; scripts. The following are probably the most common:
+      &stap; scripts. The most common conditional statements are the following:
      </para>
      <variablelist>
       <varlistentry>
@@ -1710,7 +1709,7 @@ else<co xml:id="co-tuning-systemtap-cond-else"/><replaceable>STATEMENT2</replace
         </para>
 <screen>while (<replaceable>CONDITION</replaceable>)<co xml:id="co-tuning-systemtap-cond-while"/><replaceable>STATEMENT</replaceable><co xml:id="co-tuning-systemtap-cond-while-statement"/></screen>
         <para>
-         As long as <literal>condition</literal> is non-zero, the statement
+         While <literal>condition</literal> is non-zero, the statement
          <xref linkend="co-tuning-systemtap-cond-while-statement" xrefstyle="select:label nopage"/>
          is executed.
          <xref linkend="co-tuning-systemtap-cond-while-statement" xrefstyle="select:label nopage"/>
@@ -1869,7 +1868,7 @@ probe kernel.function("tcp_accept").return?,
    except itrace is supposed to work</remark>
    For debugging user space applications (like DTrace can do),
    &productname; &productnumber; supports user space probing with
-   &stap;: Custom probe points can be inserted in any user space
+   &stap;. Custom probe points can be inserted in any user space
    application. Thus, &stap; lets you use both kernel space and user space
    probes to debug the behavior of the whole system.
   </para>
@@ -1889,9 +1888,10 @@ probe kernel.function("tcp_accept").return?,
    The engines register callback functions for specific events, then attach
    to whichever thread they want to trace. As the callbacks are made from
    <quote>safe</quote> places in the kernel, this allows for great leeway in
-   the kinds of processing the functions can do. Various events can be
-   watched via utrace, for example, system call entry and exit, fork(),
-   signals being sent to the task, etc. More details about the utrace
+   the kinds of processing the functions can do. Several events can be
+   watched via utrace. For example, you can observe events such as system call entry and exit,
+   fork(), and
+   signals being sent to the task. More details about the utrace
    infrastructure are available at
    <link xlink:href="https://sourceware.org/systemtap/wiki/utrace"/>.
   </para>
@@ -1937,7 +1937,7 @@ probe kernel.function("tcp_accept").return?,
     </term>
     <listitem>
      <para>
-      Huge collection of useful information about &stap;, ranging from
+      A large collection of useful information about &stap;, ranging from
       detailed user and developer documentation to reviews and comparisons
       with other tools, or Frequently Asked Questions and tips. Also
       contains collections of &stap; scripts, examples and usage stories