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* new-features.sgml (ov-new1.7.10): Document large address awareness

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of heap and new way to set the default heap size per executable.
	* setup2.sgml (setup-maxmem): Revamp to explain new method of
	allocating more heap on a per-executable basis.  Drop outdated stuff.
	Keep shortened description of heap_chunk_in_mb as note.
This commit is contained in:
Corinna Vinschen 2011-08-12 13:51:21 +00:00
parent ad39174691
commit 3de2809073
3 changed files with 61 additions and 44 deletions
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8
winsup/doc/ChangeLog
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@ -1,3 +1,11 @@
2011-08-12 Corinna Vinschen <corinna@vinschen.de>
* new-features.sgml (ov-new1.7.10): Document large address awareness
of heap and new way to set the default heap size per executable.
* setup2.sgml (setup-maxmem): Revamp to explain new method of
allocating more heap on a per-executable basis. Drop outdated stuff.
Keep shortened description of heap_chunk_in_mb as note.
2011-08-04 Corinna Vinschen <corinna@vinschen.de> 2011-08-04 Corinna Vinschen <corinna@vinschen.de>
* faq-using.xml (faq.using.bloda): Add NVIDIA. Change wording slightly. * faq-using.xml (faq.using.bloda): Add NVIDIA. Change wording slightly.

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winsup/doc/new-features.sgml
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@ -13,6 +13,20 @@ The CYGWIN environment variable options "envcache", "strip_title", "title",
"tty", and "upcaseenv" have been removed. "tty", and "upcaseenv" have been removed.
</para></listitem> </para></listitem>
<listitem><para>
If the executable (and the system) is large address aware, the application heap
will be placed in the large memory area. The <command>peflags</command> tool
from the <literal>rebase</literal> package can be used to set the large
address awareness flag in the executable file header.
</para></listitem>
<listitem><para>
The registry setting "heap_chunk_in_mb" has been removed, in favor of a new
per-executable setting in the executable file header which can be set using the
<command>peflags</command> tool. See <xref linkend="setup-maxmem"></xref>
for more information.
</para></listitem>
<listitem><para> <listitem><para>
The CYGWIN=tty mode using pipes to communicate with the console in a pseudo The CYGWIN=tty mode using pipes to communicate with the console in a pseudo
tty-like mode has been removed. Either just use the normal Windows console tty-like mode has been removed. Either just use the normal Windows console

83
winsup/doc/setup2.sgml
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@ -138,65 +138,60 @@ environment. In these cases, you have to call the aforementioned
Cygwin's heap is extensible. However, it does start out at a fixed size Cygwin's heap is extensible. However, it does start out at a fixed size
and attempts to extend it may run into memory which has been previously and attempts to extend it may run into memory which has been previously
allocated by Windows. In some cases, this problem can be solved by allocated by Windows. In some cases, this problem can be solved by
adding an entry in the either the <literal>HKEY_LOCAL_MACHINE</literal> changing a field in the file header which is utilized by Cygwin since
(to change the limit for all users) or version 1.7.10 to keep the initial size of the application heap. If the
<literal>HKEY_CURRENT_USER</literal> (for just the current user) section field contains 0, which is the default, the application heap defaults to
of the registry. </para> a size of 384 Megabyte. If the field is set to any other value between 4 and
2048, Cygwin tries to reserve as much Megabytes for the application heap.
The field used for this is the "LoaderFlags" field in the NT-specific
PE header structure (<literal>(IMAGE_NT_HEADER)->OptionalHeader.LoaderFlags</literal>).</para>
<para> <para>
Add the <literal>DWORD</literal> value <literal>heap_chunk_in_mb</literal> This value can be changed for any executable by using a more recent version
and set it to the desired memory limit in decimal MB. It is preferred to do of the <command>peflags</command> tool from the <literal>rebase</literal>
this in Cygwin using the <command>regtool</command> program included in the Cygwin package. Example:
Cygwin package.
(For more information about <command>regtool</command> or the other Cygwin
utilities, see <xref linkend="using-utils"></xref> or use the
<literal>--help</literal> option of each util.) You should always be careful
when using <command>regtool</command> since damaging your system registry can
result in an unusable system. This example sets memory limit to 1024 MB:
<screen> <screen>
regtool -i set /HKLM/Software/Cygwin/heap_chunk_in_mb 1024 $ peflags --cygwin-heap foo.exe
regtool -v list /HKLM/Software/Cygwin foo.exe: initial Cygwin heap size: 0 (0x0) MB
$ peflags --cygwin-heap=500 foo.exe
foo.exe: initial Cygwin heap size: 500 (0x1f4) MB
</screen> </screen>
</para> </para>
<para> <para>
Exit all running Cygwin processes and restart them. Memory can be allocated up Heap memory can be allocated up to the size of the biggest available free
to the size of the system swap space minus any the size of any running block in the processes virtual memory (VM). By default, the VM per process
processes. The system swap should be at least as large as the physically is 2 GB for 32 processes. To get more VM for a process, the executable
installed RAM and can be modified under the System category of the must have the "large address aware" flag set in the file header. You can
Control Panel. use the aforementioned <command>peflags</command> tool to set this flag.
On 64 bit systems this results in a 4 GB VM for a process started from that
executable. On 32 bit systems you also have to prepare the system to allow
up to 3 GB per process. See the Microsoft article
<ulink url="http://msdn.microsoft.com/en-us/library/bb613473%28VS.85%29.aspx">4-Gigabyte Tuning</ulink>
for more information.
</para> </para>
<note>
<para> <para>
Here is a small program written by DJ Delorie that tests the Older Cygwin releases only supported a global registry setting to
memory allocation limit on your system: change the initial heap size for all Cygwin processes. This setting is
not used anymore. However, if you're running an older Cygwin release
than 1.7.10, you can add the <literal>DWORD</literal> value
<literal>heap_chunk_in_mb</literal> and set it to the desired memory limit
in decimal MB. You have to stop all Cygwin processes for this setting to
have any effect. It is preferred to do this in Cygwin using the
<command>regtool</command> program included in the Cygwin package.
(see <xref linkend="regtool"></xref>) This example sets the memory limit
to 1024 MB for all Cygwin processes (use HKCU instead of HKLM if you
want to set this only for the current user):
<screen> <screen>
main() $ regtool -i set /HKLM/Software/Cygwin/heap_chunk_in_mb 1024
{ $ regtool -v list /HKLM/Software/Cygwin
unsigned int bit=0x40000000, sum=0;
char *x;
while (bit > 4096)
{
x = malloc(bit);
if (x)
sum += bit;
bit >>= 1;
}
printf("%08x bytes (%.1fMb)\n", sum, sum/1024.0/1024.0);
return 0;
}
</screen> </screen>
You can compile this program using:
<screen>
gcc max_memory.c -o max_memory.exe
</screen>
Run the program and it will output the maximum amount of allocatable memory.
</para> </para>
</note>
</sect1> </sect1>