Laszlo: This patch serial is good. It will improve GenFds performance if there are more padding in FD region.
Reviewed-by: Liming Gao <liming....@intel.com> Thanks Liming > -----Original Message----- > From: edk2-devel [mailto:edk2-devel-boun...@lists.01.org] On Behalf Of > Laszlo Ersek > Sent: Monday, July 11, 2016 11:55 PM > To: edk2-devel-01 <edk2-de...@ml01.01.org> > Cc: Gao, Liming <liming....@intel.com> > Subject: [edk2] [PATCH 2/2] BaseTools/GenFds: speed up Region.PadBuffer() > > 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....@intel.com> > Cc: Liming Gao <liming....@intel.com> > Contributed-under: TianoCore Contribution Agreement 1.0 > Signed-off-by: Laszlo Ersek <ler...@redhat.com> > --- > BaseTools/Source/Python/GenFds/Region.py | 9 +++++---- > 1 file changed, 5 insertions(+), 4 deletions(-) > > diff --git a/BaseTools/Source/Python/GenFds/Region.py > b/BaseTools/Source/Python/GenFds/Region.py > index 6769b39ba7e8..7548a4f014b1 100644 > --- a/BaseTools/Source/Python/GenFds/Region.py > +++ b/BaseTools/Source/Python/GenFds/Region.py > @@ -18,6 +18,7 @@ > from struct import * > from GenFdsGlobalVariable import GenFdsGlobalVariable > import StringIO > +import string > from CommonDataClass.FdfClass import RegionClassObject > import Common.LongFilePathOs as os > from stat import * > @@ -52,11 +53,11 @@ class Region(RegionClassObject): > def PadBuffer(self, Buffer, ErasePolarity, Size): > if Size > 0: > if (ErasePolarity == '1') : > - PadData = 0xFF > + PadByte = pack('B', 0xFF) > else: > - PadData = 0 > - for i in range(0, Size): > - Buffer.write(pack('B', PadData)) > + PadByte = pack('B', 0) > + PadData = string.join(PadByte for i in xrange(0, Size)) > + Buffer.write(PadData) > > ## AddToBuffer() > # > -- > 1.8.3.1 > > _______________________________________________ > edk2-devel mailing list > edk2-devel@lists.01.org > https://lists.01.org/mailman/listinfo/edk2-devel _______________________________________________ edk2-devel mailing list edk2-devel@lists.01.org https://lists.01.org/mailman/listinfo/edk2-devel
