Review Request 122487: Reorder member variables to reduce memory usage.

[Volker Krause]

> On April 16, 2015, 4:53 p.m., Milian Wolff wrote:
> > nice :) how did you find it - do you have a tool for that now or was this still requiring manual interpretation?

The tool is getting better and now also exists in a single-purpose command line version, in the above mentioned repo. Results seem to be mostly correct, unless you have incomplete DWARF data or hit some corner cases. There is still lots of work to be done on improving the optimizer to properly support bitfield packing. For just finding padding gaps it's getting somewhat usable I think.


- Volker


-----------------------------------------------------------
This is an automatically generated e-mail. To reply, visit:
https://git.reviewboard.kde.org/r/122487/#review79066
-----------------------------------------------------------


On Feb. 9, 2015, 5:04 p.m., Volker Krause wrote:
> 
> -----------------------------------------------------------
> This is an automatically generated e-mail. To reply, visit:
> https://git.reviewboard.kde.org/r/122487/
> -----------------------------------------------------------
> 
> (Updated Feb. 9, 2015, 5:04 p.m.)
> 
> 
> Review request for KDE Frameworks.
> 
> 
> Repository: kcoreaddons
> 
> 
> Description
> -------
> 
> The KJobPrivate one saves 24 bytes per instance, the others 8 bytes (on a 64 bit system).
> 
> 
> Diffs
> -----
> 
>   src/lib/io/kdirwatch_p.h f8cc2bcd5b9a8c65b409873ac78455fbb7db2405 
>   src/lib/jobs/kjob.cpp de3b8d7c8985dcc21ef9f52fba47361e9675f192 
>   src/lib/jobs/kjob_p.h 8bacefecc4dc8d2679a48b224837e0c01516d601 
>   src/lib/plugin/kpluginloader.cpp 64d7f0cec37ef51a76a3a60637822810cab398e6 
> 
> Diff: https://git.reviewboard.kde.org/r/122487/diff/
> 
> 
> Testing
> -------
> 
> ```
> Struct "Entry (DW_TAG_class_type, offset 393887)" is sub-optimally packed: 74/88 bytes, 592/704 bits, optimal size is: 80 bytes
> class KDirWatchPrivate::Entry // location: /k/kde5/src/kcoreaddons/src/lib/io/kdirwatch_p.h:83
> {
>     time_t m_ctime; // member offset: 0, size: 8, alignment: 8
>     int m_nlink; // member offset: 8, size: 4, alignment: 4
>     // 4 byte(s) padding
>     ino_t m_ino; // member offset: 16, size: 8, alignment: 8
>     entryStatus m_status; // member offset: 24, size: 4, alignment: 4
>     entryMode m_mode; // member offset: 28, size: 4, alignment: 4
>     bool isDir; // member offset: 32, size: 1, alignment: 1
>     // 7 byte(s) padding
>     QList<KDirWatchPrivate::Client*> m_clients; // member offset: 40, size: 8, alignment: 8
>     QList<KDirWatchPrivate::Entry*> m_entries; // member offset: 48, size: 8, alignment: 8
>     QString path; // member offset: 56, size: 8, alignment: 8
>     int msecLeft; // member offset: 64, size: 4, alignment: 4
>     int freq; // member offset: 68, size: 4, alignment: 4
>     bool dirty; // member offset: 72, size: 1, alignment: 1
>     // 3 byte(s) padding
>     int wd; // member offset: 76, size: 4, alignment: 4
>     QList<QString> m_pendingFileChanges; // member offset: 80, size: 8, alignment: 8
> }; // size: 88, alignment: 8
> 
> Struct "KJobPrivate (DW_TAG_class_type, offset 1112242)" is sub-optimally packed: 95/120 bytes, 760/960 bits, optimal size is: 96 bytes
> class KJobPrivate // location: /k/kde5/src/kcoreaddons/src/lib/jobs/kjob_p.h:36
> {
>     __vtbl_ptr_type* _vptr.KJobPrivate; // member offset: 0, size: 8, alignment: 8
>     KJob* q_ptr; // member offset: 8, size: 8, alignment: 8
>     KJobUiDelegate* uiDelegate; // member offset: 16, size: 8, alignment: 8
>     int error; // member offset: 24, size: 4, alignment: 4
>     // 4 byte(s) padding
>     QString errorText; // member offset: 32, size: 8, alignment: 8
>     Unit progressUnit; // member offset: 40, size: 4, alignment: 4
>     // 4 byte(s) padding
>     QMap<KJob::Unit, long long unsigned int> processedAmount; // member offset: 48, size: 8, alignment: 8
>     QMap<KJob::Unit, long long unsigned int> totalAmount; // member offset: 56, size: 8, alignment: 8
>     long unsigned int percentage; // member offset: 64, size: 8, alignment: 8
>     bool suspended; // member offset: 72, size: 1, alignment: 1
>     // 3 byte(s) padding
>     Capabilities capabilities; // member offset: 76, size: 4, alignment: 4
>     QTimer* speedTimer; // member offset: 80, size: 8, alignment: 8
>     bool isAutoDelete; // member offset: 88, size: 1, alignment: 1
>     // 7 byte(s) padding
>     QEventLoop* eventLoop; // member offset: 96, size: 8, alignment: 8
>     QEventLoopLocker eventLoopLocker; // member offset: 104, size: 8, alignment: 8
>     bool isFinished; // member offset: 112, size: 1, alignment: 1
>     // 7 byte(s) padding
> }; // size: 120, alignment: 8
> 
> Struct "KPluginLoaderPrivate (DW_TAG_class_type, offset 1584914)" is sub-optimally packed: 37/48 bytes, 296/384 bits, optimal size is: 40 bytes
> class KPluginLoaderPrivate // location: /k/kde5/src/kcoreaddons/src/lib/plugin/kpluginloader.cpp:37
> {
>     KPluginLoader* q_ptr; // member offset: 0, size: 8, alignment: 8
>     QString const name; // member offset: 8, size: 8, alignment: 8
>     quint32 pluginVersion; // member offset: 16, size: 4, alignment: 4
>     // 4 byte(s) padding
>     QString errorString; // member offset: 24, size: 8, alignment: 8
>     bool pluginVersionResolved; // member offset: 32, size: 1, alignment: 1
>     // 7 byte(s) padding
>     QPluginLoader* loader; // member offset: 40, size: 8, alignment: 8
> }; // size: 48, alignment: 8
> ```
> 
> 
> Thanks,
> 
> Volker Krause
> 
>

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.kde.org/pipermail/kde-frameworks-devel/attachments/20150416/32625f93/attachment-0001.html>