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File: [Pegasus] / pegasus / readme.sizeReduction
Revision: 1.2, Tue Dec 16 18:55:33 2008 UTC (4 years, 5 months ago) by kumpf
CVS Tags: TASK-PEP348_SCMO-root, TASK-PEP348_SCMO-merged_out_to_branch, TASK-PEP348_SCMO-merged_out_from_trunk, TASK-PEP348_SCMO-merged_in_to_trunk, TASK-PEP348_SCMO-merged_in_from_branch, TASK-PEP348_SCMO-branch, TASK-PEP317_pullop-root, TASK-PEP317_pullop-merged_out_to_branch, TASK-PEP317_pullop-merged_out_from_trunk, TASK-PEP317_pullop-merged_in_to_trunk, TASK-PEP317_pullop-merged_in_from_branch, TASK-PEP317_pullop-branch, RELEASE_2_9_2-RC2, RELEASE_2_9_2-RC1, RELEASE_2_9_2, RELEASE_2_9_1-RC1, RELEASE_2_9_1, RELEASE_2_9_0-RC1, RELEASE_2_9_0, RELEASE_2_9-root, RELEASE_2_9-branch, RELEASE_2_12_1-RC1, RELEASE_2_12_1, RELEASE_2_12_0-RC1, RELEASE_2_12_0-FC, RELEASE_2_12_0, RELEASE_2_12-root, RELEASE_2_12-branch, RELEASE_2_11_2-RC1, RELEASE_2_11_2, RELEASE_2_11_1-RC1, RELEASE_2_11_1, RELEASE_2_11_0-RC1, RELEASE_2_11_0-FC, RELEASE_2_11_0, RELEASE_2_11-root, RELEASE_2_11-branch, RELEASE_2_10_1-RC1, RELEASE_2_10_1, RELEASE_2_10_0-RC2, RELEASE_2_10_0-RC1, RELEASE_2_10_0, RELEASE_2_10-root, RELEASE_2_10-branch, HPUX_TEST, HEAD, BeforeUpdateToHeadOct82011
Changes since 1.1: +24 -24 lines
BUG#: 8273 TITLE: Remove trailing space characters DESCRIPTION: Remove meaningless whitespace.
TITLE: REDUCING PEGASUS STATIC FOOTPRINT Author: M. Brasher, Karl Schopmeyer Date: 3 Aug 2006 This readme describes how to build Pegasus for the smallest possible footprint. It defines a number of changes that you can make to reduce both the Pegasus code size and class repository size. COMPILER ISSUES 1. When using GCC, always use 4.0 or later. There are two advantages: (*) GCC 4 does a better job of optimizing C++ for size. (*) Pegasus limits symbol visisibility from shared libraries using special features of GCC 4.0 and later. 2. If you can't use at least GCC 4.0, at least try to use GCC 3.0 or better. GCC 3.0 introduced the -fno-enforce-eh-specs option, which reduces the object code size of Pegasus by 20%. 3. On 64-bit Intel systems, build 32-bit to save around 30% of the footprint (64-bit code is large since the operands are twice as long). This technique of course will produces slower code. REPOSITORY SIZE REDUCTION 1. Configure Pegasus to use a binary CIM repository. This is done by setting the PEGASUS_REPOSITORY_MODE environment variable to BIN. This technique will improve the performance of the repository. There is a readme that describes this feature. 2. Configure Pegasus to compress the CIM repository. This is done by setting the PEGASUS_ENABLE_COMPRESSED_REPOSITORY environment variable to true. This technique will slightly degrade the performance of the repository but reduce size by better than 50%. There is a readme that describes this feature and how to set it up. COMPILE OPTIONS 1. Be sure that the PEGASUS_DEBUG environment variable is not defined when you build Pegasus. Otherwise, you will end up with a much larger image. 2. Define PEGASUS_NO_FILE_LINE_TRACE=true to eliminate __FILE__ and __LINE__ macros from tracer expansion. This reduces the overall size by about 50k by not including the line and file information into the code. However, it means the resulting traces do not have this information in the trace output. 3. Turn off the compile of the trace completely. The flag PEGASUS_DISABLE_TRACE will force the compile without any of the trace code. This can save at least 100k but means that there is no means to trace including the XMLIO traces. 4. Define the PEGASUS_OPTIMIZE_FOR_SIZE environment variable that causes Pegasus to build with -Os rather than -O2. 5. Disable use of OOP. This eliminates the extra use of memory that occurs because of the extra process created to load providers. STATIC BUILD VS. DYNAMIC BUILD Originally Pegasus was built with a series of dynamic libraries, one for each source directory (common, WQL, CQL, etc.). While this has proven a good tool for developers the result is a significantly larger footprint for a number of reasons. See PEP 253 for more information. Today you have the choice of building the dynamic version or a static build which results in a much smaller footprint. Generally the static build can save up to 40% in code footprint. The same basic build mechanism is used for both static and dynamic builds with the choice being controlled by the use of two variables: PEGASUS_USE_STATIC_LIBRARIES - The environment variable PEGASUS_USE_STATIC_LIBRARIES if it exists will result in a static build. In order to determine which of the libraries go into the static build, a second variable is used in the Makefile for the libraries that are to be included in the executable. STATIC - Setting the variable STATIC=1 in the Makefile for a Pegasus component causes that component to be included in the static executable instead of building a shared library. As part of the definition of the static build mechanisms into the build environment, a lot of work was put into determining which of the existing libraries could logically be in the executable since this means that they are NOT available as shared libraries for use with providers and clients. Currently the following libraries are in the static build as supplied with the CVS Pegasus 2.6 checkout. Different users may elect to either add or remove some of these libraries from the static build depending on their needs for the availability of shared libraries for providers or clients.. src/Pegasus/Server src/Pegasus/Server/ProviderRegistrationManager src/Pegasus/Security/Authentication src/Pegasus/Security/UserManager src/Pegasus/WQL src/Pegasus/ProviderManager2 src/Pegasus/ProviderManager2/Default src/Pegasus/IndicationService src/Pegasus/ControlProviders/QueryCapabilitiesProvider src/Pegasus/ControlProviders/NamespaceProvider src/Pegasus/ControlProviders/Statistic src/Pegasus/ControlProviders/UserAuthProvider src/Pegasus/ControlProviders/InteropProvider src/Pegasus/ControlProviders/ConfigSettingProvider src/Pegasus/ControlProviders/ProviderRegistrationProvider src/Pegasus/Repository src/Pegasus/ExportServer src/Pegasus/HandlerService src/Pegasus/Query/QueryExpression src/Pegasus/Query/QueryCommon src/Pegasus/CQL src/Service NOTE: To see this list for yourself, grep -r Makefiles for STATIC=1. NOTE: This list may change with time. The components that remain dynamic libraries with are as follows: src/Pegasus/Common src/Pegasus/Client src/Pegasus/Config src/Pegasus/Provider This list represents the libraries required by providers. Building with the static build options does result in static builds for the client utilities which might include the static libraries which means that some client utilities could be significantly larger. Today you only gain if you do not use the out-of-process providers (OOP) feature because if you build static, the resulting remote agent is effectivly as large as the server because of all the static libraries that must be built into it. The steps to create a static build instead of the dynamic build: 1. Set the PEGASUS_USE_STATIC_LIBRARIES environment variable to true to cause Pegasus to use static libraries where appropriate (rather than dynamic libraries). 2. Rebuild Pegasus. This will create a single executable for the server and dynamic libraries for those components not defined to be included in the static build.
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