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-rw-r--r--system/doc/efficiency_guide/Makefile4
-rw-r--r--system/doc/efficiency_guide/advanced.xml20
-rw-r--r--system/doc/efficiency_guide/binaryhandling.xml84
-rw-r--r--system/doc/efficiency_guide/efficiency_guide.erl24
-rw-r--r--system/doc/efficiency_guide/profiling.xml2
-rw-r--r--system/doc/efficiency_guide/xmlfiles.mk2
6 files changed, 16 insertions, 120 deletions
diff --git a/system/doc/efficiency_guide/Makefile b/system/doc/efficiency_guide/Makefile
index 36e4cd00df..72bcd2ee73 100644
--- a/system/doc/efficiency_guide/Makefile
+++ b/system/doc/efficiency_guide/Makefile
@@ -1,7 +1,7 @@
#
# %CopyrightBegin%
#
-# Copyright Ericsson AB 2001-2016. All Rights Reserved.
+# Copyright Ericsson AB 2001-2018. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
@@ -28,6 +28,7 @@ include $(ERL_TOP)/erts/vsn.mk
#VSN=$(SYSTEM_VSN)
APPLICATION=otp-system-documentation
+XMLDIR := $(XMLDIR)/efficiency_guide
# ----------------------------------------------------
# Release directory specification
# ----------------------------------------------------
@@ -98,6 +99,7 @@ debug opt:
clean clean_docs:
rm -rf $(HTMLDIR)
+ rm -rf $(XMLDIR)
rm -f $(TOP_PDF_FILE) $(TOP_PDF_FILE:%.pdf=%.fo)
rm -f errs core *~
diff --git a/system/doc/efficiency_guide/advanced.xml b/system/doc/efficiency_guide/advanced.xml
index 7f719849cc..fe77ce8ea4 100644
--- a/system/doc/efficiency_guide/advanced.xml
+++ b/system/doc/efficiency_guide/advanced.xml
@@ -4,7 +4,7 @@
<chapter>
<header>
<copyright>
- <year>2001</year><year>2016</year>
+ <year>2001</year><year>2018</year>
<holder>Ericsson AB. All Rights Reserved.</holder>
</copyright>
<legalnotice>
@@ -188,16 +188,9 @@
limit can be raised or lowered using the <c>+t</c> option.</cell>
</row>
<row>
- <cell>Ets tables</cell>
- <cell>Default is 1400. It can be changed with the environment
- variable <c>ERL_MAX_ETS_TABLES</c>.</cell>
- </row>
- <row>
<cell>Elements in a tuple</cell>
- <cell>The maximum number of elements in a tuple is 67,108,863
- (26-bit unsigned integer). Clearly, other factors such as the
- available memory can make it difficult to create a tuple of
- that size.</cell>
+ <cell>The maximum number of elements in a tuple is 16,777,215
+ (24-bit unsigned integer).</cell>
</row>
<row>
<cell>Size of binary</cell>
@@ -255,10 +248,11 @@
<cell><marker id="unique_references"/>Unique References on a Runtime System Instance</cell>
<cell>Each scheduler thread has its own set of references, and all
other threads have a shared set of references. Each set of references
- consist of <c>2⁶⁴ - 1</c> unique references. That is the total
+ consist of <c>2⁶⁴ - 1</c> unique references. That is, the total
amount of unique references that can be produced on a runtime
- system instance is <c>(NoSchedulers + 1) * (2⁶⁴ - 1)</c>. If a
- scheduler thread create a new reference each nano second,
+ system instance is <c>(NoSchedulers + 1) × (2⁶⁴ - 1)</c>.
+ <br/><br/>
+ If a scheduler thread create a new reference each nano second,
references will at earliest be reused after more than 584 years.
That is, for the foreseeable future they are unique enough.</cell>
</row>
diff --git a/system/doc/efficiency_guide/binaryhandling.xml b/system/doc/efficiency_guide/binaryhandling.xml
index 19f40c9abe..b500329ef9 100644
--- a/system/doc/efficiency_guide/binaryhandling.xml
+++ b/system/doc/efficiency_guide/binaryhandling.xml
@@ -5,7 +5,7 @@
<header>
<copyright>
<year>2007</year>
- <year>2017</year>
+ <year>2018</year>
<holder>Ericsson AB, All Rights Reserved</holder>
</copyright>
<legalnotice>
@@ -357,25 +357,8 @@ all_but_zeroes_to_list(<<Byte,T/binary>>, Acc, Remaining) ->
<c>Buffer</c> from a match context to a sub binary (or do nothing if
<c>Buffer</c> is a binary already).</p>
- <p>Before you begin to think that the compiler can optimize any binary
- patterns, the following function cannot be optimized by the compiler
- (currently, at least):</p>
-
- <code type="erl"><![CDATA[
-non_opt_eq([H|T1], <<H,T2/binary>>) ->
- non_opt_eq(T1, T2);
-non_opt_eq([_|_], <<_,_/binary>>) ->
- false;
-non_opt_eq([], <<>>) ->
- true.]]></code>
-
- <p>It was mentioned earlier that the compiler can only delay creation of
- sub binaries if it knows that the binary will not be shared. In this case,
- the compiler cannot know.</p>
-
- <p>Soon it is shown how to rewrite <c>non_opt_eq/2</c> so that the delayed
- sub binary optimization can be applied, and more importantly, it is shown
- how you can find out whether your code can be optimized.</p>
+ <p>But in more complicated code, how can one know whether the
+ optimization is applied or not?</p>
<section>
<marker id="bin_opt_info"></marker>
@@ -422,67 +405,6 @@ after_zero(<<>>) ->
binary cannot be delayed, because it will be returned.
The warning for the second clause says that a sub binary will not be
created (yet).</p>
-
- <p>Let us revisit the earlier example of the code that could not
- be optimized and find out why:</p>
-
- <code type="erl"><![CDATA[
-non_opt_eq([H|T1], <<H,T2/binary>>) ->
- %% INFO: matching anything else but a plain variable to
- %% the left of binary pattern will prevent delayed
- %% sub binary optimization;
- %% SUGGEST changing argument order
- %% NOT OPTIMIZED: called function non_opt_eq/2 does not
- %% begin with a suitable binary matching instruction
- non_opt_eq(T1, T2);
-non_opt_eq([_|_], <<_,_/binary>>) ->
- false;
-non_opt_eq([], <<>>) ->
- true.]]></code>
-
- <p>The compiler emitted two warnings. The <c>INFO</c> warning refers
- to the function <c>non_opt_eq/2</c> as a callee, indicating that any
- function that call <c>non_opt_eq/2</c> cannot make delayed sub binary
- optimization. There is also a suggestion to change argument order.
- The second warning (that happens to refer to the same line) refers to
- the construction of the sub binary itself.</p>
-
- <p>Soon another example will show the difference between the
- <c>INFO</c> and <c>NOT OPTIMIZED</c> warnings somewhat clearer, but
- let us first follow the suggestion to change argument order:</p>
-
- <code type="erl"><![CDATA[
-opt_eq(<<H,T1/binary>>, [H|T2]) ->
- %% OPTIMIZED: creation of sub binary delayed
- opt_eq(T1, T2);
-opt_eq(<<_,_/binary>>, [_|_]) ->
- false;
-opt_eq(<<>>, []) ->
- true.]]></code>
-
- <p>The compiler gives a warning for the following code fragment:</p>
-
- <code type="erl"><![CDATA[
-match_body([0|_], <<H,_/binary>>) ->
- %% INFO: matching anything else but a plain variable to
- %% the left of binary pattern will prevent delayed
- %% sub binary optimization;
- %% SUGGEST changing argument order
- done;
-...]]></code>
-
- <p>The warning means that <em>if</em> there is a call to <c>match_body/2</c>
- (from another clause in <c>match_body/2</c> or another function), the
- delayed sub binary optimization will not be possible. More warnings will
- occur for any place where a sub binary is matched out at the end of and
- passed as the second argument to <c>match_body/2</c>, for example:</p>
-
- <code type="erl"><![CDATA[
-match_head(List, <<_:10,Data/binary>>) ->
- %% NOT OPTIMIZED: called function match_body/2 does not
- %% begin with a suitable binary matching instruction
- match_body(List, Data).]]></code>
-
</section>
<section>
diff --git a/system/doc/efficiency_guide/efficiency_guide.erl b/system/doc/efficiency_guide/efficiency_guide.erl
index e982bdae65..c57785aaa3 100644
--- a/system/doc/efficiency_guide/efficiency_guide.erl
+++ b/system/doc/efficiency_guide/efficiency_guide.erl
@@ -1,5 +1,5 @@
-module(efficiency_guide).
--compile(export_all).
+-compile([export_all,nowarn_export_all).
%% DO NOT
naive_reverse([H|T]) ->
@@ -71,28 +71,6 @@ all_but_zeroes_to_list(<<0,T/binary>>, Acc, Remaining) ->
all_but_zeroes_to_list(<<Byte,T/binary>>, Acc, Remaining) ->
all_but_zeroes_to_list(T, [Byte|Acc], Remaining-1).
-non_opt_eq([H|T1], <<H,T2/binary>>) ->
- non_opt_eq(T1, T2);
-non_opt_eq([_|_], <<_,_/binary>>) ->
- false;
-non_opt_eq([], <<>>) ->
- true.
-
-opt_eq(<<H,T1/binary>>, [H|T2]) ->
- opt_eq(T1, T2);
-opt_eq(<<_,_/binary>>, [_|_]) ->
- false;
-opt_eq(<<>>, []) ->
- true.
-
-match_head(List, <<_:10,Data/binary>>) ->
- match_body(List, Data).
-
-match_body([0|_], <<H,_/binary>>) ->
- done;
-match_body([H|T1], <<H,T2/binary>>) ->
- {T1,T2}.
-
count1(<<_,T/binary>>, Count) -> count1(T, Count+1);
count1(<<>>, Count) -> Count.
diff --git a/system/doc/efficiency_guide/profiling.xml b/system/doc/efficiency_guide/profiling.xml
index f185456158..cdc80289cf 100644
--- a/system/doc/efficiency_guide/profiling.xml
+++ b/system/doc/efficiency_guide/profiling.xml
@@ -4,7 +4,7 @@
<chapter>
<header>
<copyright>
- <year>2001</year><year>2016</year>
+ <year>2001</year><year>2018</year>
<holder>Ericsson AB. All Rights Reserved.</holder>
</copyright>
<legalnotice>
diff --git a/system/doc/efficiency_guide/xmlfiles.mk b/system/doc/efficiency_guide/xmlfiles.mk
index 23c0d991b4..e275823dd1 100644
--- a/system/doc/efficiency_guide/xmlfiles.mk
+++ b/system/doc/efficiency_guide/xmlfiles.mk
@@ -1,7 +1,7 @@
#
# %CopyrightBegin%
#
-# Copyright Ericsson AB 2009-2016. All Rights Reserved.
+# Copyright Ericsson AB 2009-2018. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
generated by cgit v1.2.3 (git 2.25.1) at 2024-09-03 00:24:24 +0000