bd907fb638
The current implementation calls both pack() and Buffer.write() Size
times. The new implementation calls both of these methods only once; the
full data to write are constructed locally [1]. The range() function is
replaced by xrange() because the latter is supposed to be faster / lighter
weight [2].
On my laptop, I tested the change as follows: I pre-built the series at
[3] with
build -a X64 -p OvmfPkg/OvmfPkgX64.dsc -t GCC48 -b DEBUG \
-D HTTP_BOOT_ENABLE -D SECURE_BOOT_ENABLE
(The series at [3] is relevant because it increases the size of one of the
padded regions by 8.5 MB, slowing down the build quite a bit.)
With all source code already compiled, repeating the above command takes
approximately 45 seconds. With the patch applied, it goes down to 29
seconds.
[1] http://stackoverflow.com/questions/27384093/fastest-way-to-write-huge-data-in-file
[2] https://docs.python.org/2/library/functions.html?highlight=xrange#xrange
[3] http://thread.gmane.org/gmane.comp.bios.edk2.devel/14214
We can also measure the impact with a synthetic test:
> import timeit
>
> test_old = """
> import struct, string, StringIO
> Size = (8 * 1024 + 512) * 1024
> Buffer = StringIO.StringIO()
> PadData = 0xFF
> for i in range(0, Size):
> Buffer.write(struct.pack('B', PadData))
> """
>
> test_new = """
> import struct, string, StringIO
> Size = (8 * 1024 + 512) * 1024
> Buffer = StringIO.StringIO()
> PadByte = struct.pack('B', 0xFF)
> PadData = string.join(PadByte for i in xrange(0, Size))
> Buffer.write(PadData)
> """
>
> print(timeit.repeat(stmt=test_old, number=1, repeat=3))
> print(timeit.repeat(stmt=test_new, number=1, repeat=3))
The output is
[8.231637001037598, 8.81188416481018, 8.948754072189331]
[0.5503702163696289, 0.5461571216583252, 0.578315019607544]
Cc: Yonghong Zhu <yonghong.zhu@intel.com>
Cc: Liming Gao <liming.gao@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>
This directory contains the next generation of EDK II build tools and template files. Templates are located in the Conf directory, while the tools executables for Microsoft Windows 32-bit Operating Systems are located in the Bin\Win32 directory, other directory contatins tools source. 1. Build step to generate the binary tools. === Windows/Visual Studio Notes === To build the BaseTools, you should run the standard vsvars32.bat script from your preferred Visual Studio installation or you can run get_vsvars.bat to use latest automatically detected version. In addition to this, you should set the following environment variables: * EDK_TOOLS_PATH - Path to the BaseTools sub directory under the edk2 tree * BASE_TOOLS_PATH - The directory where the BaseTools source is located. (It is the same directory where this README.txt is located.) * PYTHON_FREEZER_PATH - Path to where the python freezer tool is installed After this, you can run the toolsetup.bat file, which is in the same directory as this file. It should setup the remainder of the environment, and build the tools if necessary. Please also refer to the 'BuildNotes.txt' file for more information on building under Windows. === Unix-like operating systems === To build on Unix-like operating systems, you only need to type 'make' in the base directory of the project. === Ubuntu Notes === On Ubuntu, the following command should install all the necessary build packages to build all the C BaseTools: sudo apt-get install build-essential uuid-dev === Python sqlite3 module === On Windows, the cx_freeze will not copy the sqlite3.dll to the frozen binary directory (the same directory as build.exe and GenFds.exe). Please copy it manually from <PythonHome>\DLLs. The Python distributed with most recent Linux will have sqlite3 module built in. If not, please install sqlit3 package separately. 26-OCT-2011