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| author | alk3pInjection <webmaster@raspii.tech> | 2024-02-04 16:16:35 +0800 |
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| committer | alk3pInjection <webmaster@raspii.tech> | 2024-02-04 16:16:35 +0800 |
| commit | 6ce4ebed87858ecdd79a1091367c6e961055daa9 (patch) | |
| tree | 1c2a6a60531acf791531bbd9c8ac14c23ef8a66c /share/doc/gdb/Caching-Target-Data.html | |
https://developer.arm.com/downloads/-/arm-gnu-toolchain-downloads
Change-Id: I7303388733328cd98ab9aa3c30236db67f2e9e9c
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diff --git a/share/doc/gdb/Caching-Target-Data.html b/share/doc/gdb/Caching-Target-Data.html new file mode 100644 index 0000000..abee415 --- /dev/null +++ b/share/doc/gdb/Caching-Target-Data.html @@ -0,0 +1,194 @@ +<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> +<html> +<!-- Copyright (C) 1988-2023 Free Software Foundation, Inc. + +Permission is granted to copy, distribute and/or modify this document +under the terms of the GNU Free Documentation License, Version 1.3 or +any later version published by the Free Software Foundation; with the +Invariant Sections being "Free Software" and "Free Software Needs +Free Documentation", with the Front-Cover Texts being "A GNU Manual," +and with the Back-Cover Texts as in (a) below. + +(a) The FSF's Back-Cover Text is: "You are free to copy and modify +this GNU Manual. Buying copies from GNU Press supports the FSF in +developing GNU and promoting software freedom." --> +<!-- Created by GNU Texinfo 5.1, http://www.gnu.org/software/texinfo/ --> +<head> +<title>Debugging with GDB: Caching Target Data</title> + +<meta name="description" content="Debugging with GDB: Caching Target Data"> +<meta name="keywords" content="Debugging with GDB: Caching Target Data"> +<meta name="resource-type" content="document"> +<meta name="distribution" content="global"> +<meta name="Generator" content="makeinfo"> +<meta http-equiv="Content-Type" content="text/html; charset=utf-8"> +<link href="index.html#Top" rel="start" title="Top"> +<link href="Concept-Index.html#Concept-Index" rel="index" title="Concept Index"> +<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents"> +<link href="Data.html#Data" rel="up" title="Data"> +<link href="Searching-Memory.html#Searching-Memory" rel="next" title="Searching Memory"> +<link href="Character-Sets.html#Character-Sets" rel="previous" title="Character Sets"> +<style type="text/css"> +<!-- +a.summary-letter {text-decoration: none} +blockquote.smallquotation {font-size: smaller} +div.display {margin-left: 3.2em} +div.example {margin-left: 3.2em} +div.indentedblock {margin-left: 3.2em} +div.lisp {margin-left: 3.2em} +div.smalldisplay {margin-left: 3.2em} +div.smallexample {margin-left: 3.2em} +div.smallindentedblock {margin-left: 3.2em; font-size: smaller} +div.smalllisp {margin-left: 3.2em} +kbd {font-style:oblique} +pre.display {font-family: inherit} +pre.format {font-family: inherit} +pre.menu-comment {font-family: serif} +pre.menu-preformatted {font-family: serif} +pre.smalldisplay {font-family: inherit; font-size: smaller} +pre.smallexample {font-size: smaller} +pre.smallformat {font-family: inherit; font-size: smaller} +pre.smalllisp {font-size: smaller} +span.nocodebreak {white-space:nowrap} +span.nolinebreak {white-space:nowrap} +span.roman {font-family:serif; font-weight:normal} +span.sansserif {font-family:sans-serif; font-weight:normal} +ul.no-bullet {list-style: none} +--> +</style> + + +</head> + +<body lang="en" bgcolor="#FFFFFF" text="#000000" link="#0000FF" vlink="#800080" alink="#FF0000"> +<a name="Caching-Target-Data"></a> +<div class="header"> +<p> +Next: <a href="Searching-Memory.html#Searching-Memory" accesskey="n" rel="next">Searching Memory</a>, Previous: <a href="Character-Sets.html#Character-Sets" accesskey="p" rel="previous">Character Sets</a>, Up: <a href="Data.html#Data" accesskey="u" rel="up">Data</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html#Concept-Index" title="Index" rel="index">Index</a>]</p> +</div> +<hr> +<a name="Caching-Data-of-Targets"></a> +<h3 class="section">10.22 Caching Data of Targets</h3> +<a name="index-caching-data-of-targets"></a> + +<p><small>GDB</small> caches data exchanged between the debugger and a target. +Each cache is associated with the address space of the inferior. +See <a href="Inferiors-Connections-and-Programs.html#Inferiors-Connections-and-Programs">Inferiors Connections and Programs</a>, about inferior and address space. +Such caching generally improves performance in remote debugging +(see <a href="Remote-Debugging.html#Remote-Debugging">Remote Debugging</a>), because it reduces the overhead of the +remote protocol by bundling memory reads and writes into large chunks. +Unfortunately, simply caching everything would lead to incorrect results, +since <small>GDB</small> does not necessarily know anything about volatile +values, memory-mapped I/O addresses, etc. Furthermore, in non-stop mode +(see <a href="Non_002dStop-Mode.html#Non_002dStop-Mode">Non-Stop Mode</a>) memory can be changed <em>while</em> a gdb command +is executing. +Therefore, by default, <small>GDB</small> only caches data +known to be on the stack<a name="DOCF13" href="#FOOT13"><sup>13</sup></a> or +in the code segment. +Other regions of memory can be explicitly marked as +cacheable; see <a href="Memory-Region-Attributes.html#Memory-Region-Attributes">Memory Region Attributes</a>. +</p> +<dl compact="compact"> +<dd><a name="index-set-remotecache"></a> +</dd> +<dt><code>set remotecache on</code></dt> +<dt><code>set remotecache off</code></dt> +<dd><p>This option no longer does anything; it exists for compatibility +with old scripts. +</p> +<a name="index-show-remotecache"></a> +</dd> +<dt><code>show remotecache</code></dt> +<dd><p>Show the current state of the obsolete remotecache flag. +</p> +<a name="index-set-stack_002dcache"></a> +</dd> +<dt><code>set stack-cache on</code></dt> +<dt><code>set stack-cache off</code></dt> +<dd><p>Enable or disable caching of stack accesses. When <code>on</code>, use +caching. By default, this option is <code>on</code>. +</p> +<a name="index-show-stack_002dcache"></a> +</dd> +<dt><code>show stack-cache</code></dt> +<dd><p>Show the current state of data caching for memory accesses. +</p> +<a name="index-set-code_002dcache"></a> +</dd> +<dt><code>set code-cache on</code></dt> +<dt><code>set code-cache off</code></dt> +<dd><p>Enable or disable caching of code segment accesses. When <code>on</code>, +use caching. By default, this option is <code>on</code>. This improves +performance of disassembly in remote debugging. +</p> +<a name="index-show-code_002dcache"></a> +</dd> +<dt><code>show code-cache</code></dt> +<dd><p>Show the current state of target memory cache for code segment +accesses. +</p> +<a name="index-info-dcache"></a> +</dd> +<dt><code>info dcache <span class="roman">[</span>line<span class="roman">]</span></code></dt> +<dd><p>Print the information about the performance of data cache of the +current inferior’s address space. The information displayed +includes the dcache width and depth, and for each cache line, its +number, address, and how many times it was referenced. This +command is useful for debugging the data cache operation. +</p> +<p>If a line number is specified, the contents of that line will be +printed in hex. +</p> +</dd> +<dt><code>set dcache size <var>size</var></code></dt> +<dd><a name="index-dcache-size"></a> +<a name="index-set-dcache-size"></a> +<p>Set maximum number of entries in dcache (dcache depth above). +</p> +</dd> +<dt><code>set dcache line-size <var>line-size</var></code></dt> +<dd><a name="index-dcache-line_002dsize"></a> +<a name="index-set-dcache-line_002dsize"></a> +<p>Set number of bytes each dcache entry caches (dcache width above). +Must be a power of 2. +</p> +</dd> +<dt><code>show dcache size</code></dt> +<dd><a name="index-show-dcache-size"></a> +<p>Show maximum number of dcache entries. See <a href="#Caching-Target-Data">info dcache</a>. +</p> +</dd> +<dt><code>show dcache line-size</code></dt> +<dd><a name="index-show-dcache-line_002dsize"></a> +<p>Show default size of dcache lines. +</p> +</dd> +<dt><code>maint flush dcache</code></dt> +<dd><a name="index-dcache_002c-flushing"></a> +<a name="index-maint-flush-dcache"></a> +<p>Flush the contents (if any) of the dcache. This maintainer command is +useful when debugging the dcache implementation. +</p> +</dd> +</dl> + +<div class="footnote"> +<hr> +<h4 class="footnotes-heading">Footnotes</h4> + +<h3><a name="FOOT13" href="#DOCF13">(13)</a></h3> +<p>In non-stop mode, it is moderately +rare for a running thread to modify the stack of a stopped thread +in a way that would interfere with a backtrace, and caching of +stack reads provides a significant speed up of remote backtraces.</p> +</div> +<hr> +<div class="header"> +<p> +Next: <a href="Searching-Memory.html#Searching-Memory" accesskey="n" rel="next">Searching Memory</a>, Previous: <a href="Character-Sets.html#Character-Sets" accesskey="p" rel="previous">Character Sets</a>, Up: <a href="Data.html#Data" accesskey="u" rel="up">Data</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html#Concept-Index" title="Index" rel="index">Index</a>]</p> +</div> + + + +</body> +</html> |