€•nj      Œsphinx.addnodes”Œdocument”“”)”}”(Œ	rawsource”Œ ”Œchildren”]”(Œtranslations”ŒLanguagesNode”“”)”}”(hhh]”(h Œpending_xref”“”)”}”(hhh]”Œdocutils.nodes”ŒText”“”ŒChinese (Simplified)”…””}”Œparent”hsbaŒ
attributes”}”(Œids”]”Œclasses”]”Œnames”]”Œdupnames”]”Œbackrefs”]”Œ	refdomain”Œstd”Œreftype”Œdoc”Œ	reftarget”Œ'/translations/zh_CN/dev-tools/propeller”Œmodname”NŒ	classname”NŒrefexplicit”ˆuŒtagname”hhhubh)”}”(hhh]”hŒChinese (Traditional)”…””}”hh2sbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ'/translations/zh_TW/dev-tools/propeller”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒItalian”…””}”hhFsbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ'/translations/it_IT/dev-tools/propeller”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒJapanese”…””}”hhZsbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ'/translations/ja_JP/dev-tools/propeller”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒKorean”…””}”hhnsbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ'/translations/ko_KR/dev-tools/propeller”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒSpanish”…””}”hh‚sbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ'/translations/sp_SP/dev-tools/propeller”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubeh}”(h]”h ]”h"]”h$]”h&]”Œcurrent_language”ŒEnglish”uh1h
hhŒ	_document”hŒsource”NŒline”NubhŒcomment”“”)”}”(hŒ SPDX-License-Identifier: GPL-2.0”h]”hŒ SPDX-License-Identifier: GPL-2.0”…””}”hh£sbah}”(h]”h ]”h"]”h$]”h&]”Œ	xml:space”Œpreserve”uh1h¡hhhžhhŸŒA/var/lib/git/docbuild/linux/Documentation/dev-tools/propeller.rst”h KubhŒsection”“”)”}”(hhh]”(hŒtitle”“”)”}”(hŒ%Using Propeller with the Linux kernel”h]”hŒ%Using Propeller with the Linux kernel”…””}”(hh»hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¹hh¶hžhhŸh³h KubhŒ	paragraph”“”)”}”(hXÅ  This enables Propeller build support for the kernel when using Clang
compiler. Propeller is a profile-guided optimization (PGO) method used
to optimize binary executables. Like AutoFDO, it utilizes hardware
sampling to gather information about the frequency of execution of
different code paths within a binary. Unlike AutoFDO, this information
is then used right before linking phase to optimize (among others)
block layout within and across functions.”h]”hXÅ  This enables Propeller build support for the kernel when using Clang
compiler. Propeller is a profile-guided optimization (PGO) method used
to optimize binary executables. Like AutoFDO, it utilizes hardware
sampling to gather information about the frequency of execution of
different code paths within a binary. Unlike AutoFDO, this information
is then used right before linking phase to optimize (among others)
block layout within and across functions.”…””}”(hhËhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h Khh¶hžhubhÊ)”}”(hŒ<A few important notes about adopting Propeller optimization:”h]”hŒ<A few important notes about adopting Propeller optimization:”…””}”(hhÙhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h Khh¶hžhubhŒenumerated_list”“”)”}”(hhh]”(hŒ	list_item”“”)”}”(hŒÐAlthough it can be used as a standalone optimization step, it is
strongly recommended to apply Propeller on top of AutoFDO,
AutoFDO+ThinLTO or Instrument FDO. The rest of this document
assumes this paradigm.
”h]”hÊ)”}”(hŒÏAlthough it can be used as a standalone optimization step, it is
strongly recommended to apply Propeller on top of AutoFDO,
AutoFDO+ThinLTO or Instrument FDO. The rest of this document
assumes this paradigm.”h]”hŒÏAlthough it can be used as a standalone optimization step, it is
strongly recommended to apply Propeller on top of AutoFDO,
AutoFDO+ThinLTO or Instrument FDO. The rest of this document
assumes this paradigm.”…””}”(hhòhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h Khhîubah}”(h]”h ]”h"]”h$]”h&]”uh1hìhhéhžhhŸh³h Nubhí)”}”(hŒÄPropeller uses another round of profiling on top of
AutoFDO/AutoFDO+ThinLTO/iFDO. The whole build process involves
"build-afdo - train-afdo - build-propeller - train-propeller -
build-optimized".
”h]”hÊ)”}”(hŒÃPropeller uses another round of profiling on top of
AutoFDO/AutoFDO+ThinLTO/iFDO. The whole build process involves
"build-afdo - train-afdo - build-propeller - train-propeller -
build-optimized".”h]”hŒÇPropeller uses another round of profiling on top of
AutoFDO/AutoFDO+ThinLTO/iFDO. The whole build process involves
â€œbuild-afdo - train-afdo - build-propeller - train-propeller -
build-optimizedâ€.”…””}”(hj
  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h Khj  ubah}”(h]”h ]”h"]”h$]”h&]”uh1hìhhéhžhhŸh³h Nubhí)”}”(hŒVPropeller requires LLVM 19 release or later for Clang/Clang++
and the linker(ld.lld).
”h]”hÊ)”}”(hŒUPropeller requires LLVM 19 release or later for Clang/Clang++
and the linker(ld.lld).”h]”hŒUPropeller requires LLVM 19 release or later for Clang/Clang++
and the linker(ld.lld).”…””}”(hj"  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h Khj  ubah}”(h]”h ]”h"]”h$]”h&]”uh1hìhhéhžhhŸh³h Nubhí)”}”(hŒÇIn addition to LLVM toolchain, Propeller requires a profiling
conversion tool: https://github.com/google/autofdo with a release
after v0.30.1: https://github.com/google/autofdo/releases/tag/v0.30.1.
”h]”hÊ)”}”(hŒÆIn addition to LLVM toolchain, Propeller requires a profiling
conversion tool: https://github.com/google/autofdo with a release
after v0.30.1: https://github.com/google/autofdo/releases/tag/v0.30.1.”h]”(hŒOIn addition to LLVM toolchain, Propeller requires a profiling
conversion tool: ”…””}”(hj:  hžhhŸNh NubhŒ	reference”“”)”}”(hŒ!https://github.com/google/autofdo”h]”hŒ!https://github.com/google/autofdo”…””}”(hjD  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”Œrefuri”jF  uh1jB  hj:  ubhŒ with a release
after v0.30.1: ”…””}”(hj:  hžhhŸNh NubjC  )”}”(hŒ6https://github.com/google/autofdo/releases/tag/v0.30.1”h]”hŒ6https://github.com/google/autofdo/releases/tag/v0.30.1”…””}”(hjW  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”Œrefuri”jY  uh1jB  hj:  ubhŒ.”…””}”(hj:  hžhhŸNh Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h Khj6  ubah}”(h]”h ]”h"]”h$]”h&]”uh1hìhhéhžhhŸh³h Nubeh}”(h]”h ]”h"]”h$]”h&]”Œenumtype”Œarabic”Œprefix”hŒsuffix”Œ.”uh1hçhh¶hžhhŸh³h KubhÊ)”}”(hŒ@The Propeller optimization process involves the following steps:”h]”hŒ@The Propeller optimization process involves the following steps:”…””}”(hj  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h K"hh¶hžhubhè)”}”(hhh]”(hí)”}”(hXn  Initial building: Build the AutoFDO or AutoFDO+ThinLTO binary as
you would normally do, but with a set of compile-time / link-time
flags, so that a special metadata section is created within the
kernel binary. The special section is only intend to be used by the
profiling tool, it is not part of the runtime image, nor does it
change kernel run time text sections.
”h]”hÊ)”}”(hXm  Initial building: Build the AutoFDO or AutoFDO+ThinLTO binary as
you would normally do, but with a set of compile-time / link-time
flags, so that a special metadata section is created within the
kernel binary. The special section is only intend to be used by the
profiling tool, it is not part of the runtime image, nor does it
change kernel run time text sections.”h]”hXm  Initial building: Build the AutoFDO or AutoFDO+ThinLTO binary as
you would normally do, but with a set of compile-time / link-time
flags, so that a special metadata section is created within the
kernel binary. The special section is only intend to be used by the
profiling tool, it is not part of the runtime image, nor does it
change kernel run time text sections.”…””}”(hj–  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h K$hj’  ubah}”(h]”h ]”h"]”h$]”h&]”uh1hìhj  hžhhŸh³h Nubhí)”}”(hXs  Profiling: The above kernel is then run with a representative
workload to gather execution frequency data. This data is collected
using hardware sampling, via perf. Propeller is most effective on
platforms supporting advanced PMU features like LBR on Intel
machines. This step is the same as profiling the kernel for AutoFDO
(the exact perf parameters can be different).
”h]”hÊ)”}”(hXr  Profiling: The above kernel is then run with a representative
workload to gather execution frequency data. This data is collected
using hardware sampling, via perf. Propeller is most effective on
platforms supporting advanced PMU features like LBR on Intel
machines. This step is the same as profiling the kernel for AutoFDO
(the exact perf parameters can be different).”h]”hXr  Profiling: The above kernel is then run with a representative
workload to gather execution frequency data. This data is collected
using hardware sampling, via perf. Propeller is most effective on
platforms supporting advanced PMU features like LBR on Intel
machines. This step is the same as profiling the kernel for AutoFDO
(the exact perf parameters can be different).”…””}”(hj®  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h K+hjª  ubah}”(h]”h ]”h"]”h$]”h&]”uh1hìhj  hžhhŸh³h Nubhí)”}”(hŒqPropeller profile generation: Perf output file is converted to a
pair of Propeller profiles via an offline tool.
”h]”hÊ)”}”(hŒpPropeller profile generation: Perf output file is converted to a
pair of Propeller profiles via an offline tool.”h]”hŒpPropeller profile generation: Perf output file is converted to a
pair of Propeller profiles via an offline tool.”…””}”(hjÆ  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h K2hjÂ  ubah}”(h]”h ]”h"]”h$]”h&]”uh1hìhj  hžhhŸh³h Nubhí)”}”(hXG  Optimized build: Build the AutoFDO or AutoFDO+ThinLTO optimized
binary as you would normally do, but with a compile-time /
link-time flag to pick up the Propeller compile time and link time
profiles. This build step uses 3 profiles - the AutoFDO profile,
the Propeller compile-time profile and the Propeller link-time
profile.
”h]”hÊ)”}”(hXF  Optimized build: Build the AutoFDO or AutoFDO+ThinLTO optimized
binary as you would normally do, but with a compile-time /
link-time flag to pick up the Propeller compile time and link time
profiles. This build step uses 3 profiles - the AutoFDO profile,
the Propeller compile-time profile and the Propeller link-time
profile.”h]”hXF  Optimized build: Build the AutoFDO or AutoFDO+ThinLTO optimized
binary as you would normally do, but with a compile-time /
link-time flag to pick up the Propeller compile time and link time
profiles. This build step uses 3 profiles - the AutoFDO profile,
the Propeller compile-time profile and the Propeller link-time
profile.”…””}”(hjÞ  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h K5hjÚ  ubah}”(h]”h ]”h"]”h$]”h&]”uh1hìhj  hžhhŸh³h Nubhí)”}”(hŒDeployment: The optimized kernel binary is deployed and used
in production environments, providing improved performance
and reduced latency.
”h]”hÊ)”}”(hŒŒDeployment: The optimized kernel binary is deployed and used
in production environments, providing improved performance
and reduced latency.”h]”hŒŒDeployment: The optimized kernel binary is deployed and used
in production environments, providing improved performance
and reduced latency.”…””}”(hjö  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h K<hjò  ubah}”(h]”h ]”h"]”h$]”h&]”uh1hìhj  hžhhŸh³h Nubeh}”(h]”h ]”h"]”h$]”h&]”j|  j}  j~  hj  j€  uh1hçhh¶hžhhŸh³h K$ubhµ)”}”(hhh]”(hº)”}”(hŒPreparation”h]”hŒPreparation”…””}”(hj  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¹hj  hžhhŸh³h KAubhÊ)”}”(hŒConfigure the kernel with::”h]”hŒConfigure the kernel with:”…””}”(hj!  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h KChj  hžhubhŒliteral_block”“”)”}”(hŒ/CONFIG_AUTOFDO_CLANG=y
CONFIG_PROPELLER_CLANG=y”h]”hŒ/CONFIG_AUTOFDO_CLANG=y
CONFIG_PROPELLER_CLANG=y”…””}”hj1  sbah}”(h]”h ]”h"]”h$]”h&]”h±h²uh1j/  hŸh³h KEhj  hžhubeh}”(h]”Œpreparation”ah ]”h"]”Œpreparation”ah$]”h&]”uh1h´hh¶hžhhŸh³h KAubhµ)”}”(hhh]”(hº)”}”(hŒCustomization”h]”hŒCustomization”…””}”(hjJ  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¹hjG  hžhhŸh³h KIubhÊ)”}”(hX  The default CONFIG_PROPELLER_CLANG setting covers kernel space objects
for Propeller builds. One can, however, enable or disable Propeller build
for individual files and directories by adding a line similar to the
following to the respective kernel Makefile:”h]”hX  The default CONFIG_PROPELLER_CLANG setting covers kernel space objects
for Propeller builds. One can, however, enable or disable Propeller build
for individual files and directories by adding a line similar to the
following to the respective kernel Makefile:”…””}”(hjX  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h KKhjG  hžhubhŒbullet_list”“”)”}”(hhh]”(hí)”}”(hŒIFor enabling a single file (e.g. foo.o)::

 PROPELLER_PROFILE_foo.o := y
”h]”(hÊ)”}”(hŒ)For enabling a single file (e.g. foo.o)::”h]”hŒ(For enabling a single file (e.g. foo.o):”…””}”(hjo  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h KPhjk  ubj0  )”}”(hŒPROPELLER_PROFILE_foo.o := y”h]”hŒPROPELLER_PROFILE_foo.o := y”…””}”hj}  sbah}”(h]”h ]”h"]”h$]”h&]”h±h²uh1j/  hŸh³h KRhjk  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1hìhjh  hžhhŸh³h Nubhí)”}”(hŒCFor enabling all files in one directory::

 PROPELLER_PROFILE := y
”h]”(hÊ)”}”(hŒ)For enabling all files in one directory::”h]”hŒ(For enabling all files in one directory:”…””}”(hj•  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h KThj‘  ubj0  )”}”(hŒPROPELLER_PROFILE := y”h]”hŒPROPELLER_PROFILE := y”…””}”hj£  sbah}”(h]”h ]”h"]”h$]”h&]”h±h²uh1j/  hŸh³h KVhj‘  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1hìhjh  hžhhŸh³h Nubhí)”}”(hŒ8For disabling one file::

 PROPELLER_PROFILE_foo.o := n
”h]”(hÊ)”}”(hŒFor disabling one file::”h]”hŒFor disabling one file:”…””}”(hj»  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h KXhj·  ubj0  )”}”(hŒPROPELLER_PROFILE_foo.o := n”h]”hŒPROPELLER_PROFILE_foo.o := n”…””}”hjÉ  sbah}”(h]”h ]”h"]”h$]”h&]”h±h²uh1j/  hŸh³h KZhj·  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1hìhjh  hžhhŸh³h Nubhí)”}”(hŒFFor disabling all files in one directory::

 PROPELLER__PROFILE := n

”h]”(hÊ)”}”(hŒ*For disabling all files in one directory::”h]”hŒ)For disabling all files in one directory:”…””}”(hjá  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h K\hjÝ  ubj0  )”}”(hŒPROPELLER__PROFILE := n”h]”hŒPROPELLER__PROFILE := n”…””}”hjï  sbah}”(h]”h ]”h"]”h$]”h&]”h±h²uh1j/  hŸh³h K^hjÝ  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1hìhjh  hžhhŸh³h Nubeh}”(h]”h ]”h"]”h$]”h&]”Œbullet”Œ-”uh1jf  hŸh³h KPhjG  hžhubeh}”(h]”Œcustomization”ah ]”h"]”Œcustomization”ah$]”h&]”uh1h´hh¶hžhhŸh³h KIubhµ)”}”(hhh]”(hº)”}”(hŒWorkflow”h]”hŒWorkflow”…””}”(hj  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¹hj  hžhhŸh³h KbubhÊ)”}”(hŒEHere is an example workflow for building an AutoFDO+Propeller kernel:”h]”hŒEHere is an example workflow for building an AutoFDO+Propeller kernel:”…””}”(hj$  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h Kdhj  hžhubhè)”}”(hhh]”(hí)”}”(hX1  Assuming an AutoFDO profile is already collected following
instructions in the AutoFDO document, build the kernel on the host
machine, with AutoFDO and Propeller build configs ::

   CONFIG_AUTOFDO_CLANG=y
   CONFIG_PROPELLER_CLANG=y

and ::

   $ make LLVM=1 CLANG_AUTOFDO_PROFILE=<autofdo-profile-name>
”h]”(hÊ)”}”(hŒ²Assuming an AutoFDO profile is already collected following
instructions in the AutoFDO document, build the kernel on the host
machine, with AutoFDO and Propeller build configs ::”h]”hŒ¯Assuming an AutoFDO profile is already collected following
instructions in the AutoFDO document, build the kernel on the host
machine, with AutoFDO and Propeller build configs”…””}”(hj9  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h Kfhj5  ubj0  )”}”(hŒ/CONFIG_AUTOFDO_CLANG=y
CONFIG_PROPELLER_CLANG=y”h]”hŒ/CONFIG_AUTOFDO_CLANG=y
CONFIG_PROPELLER_CLANG=y”…””}”hjG  sbah}”(h]”h ]”h"]”h$]”h&]”h±h²uh1j/  hŸh³h Kjhj5  ubhÊ)”}”(hŒand ::”h]”hŒand”…””}”(hjU  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h Kmhj5  ubj0  )”}”(hŒ:$ make LLVM=1 CLANG_AUTOFDO_PROFILE=<autofdo-profile-name>”h]”hŒ:$ make LLVM=1 CLANG_AUTOFDO_PROFILE=<autofdo-profile-name>”…””}”hjc  sbah}”(h]”h ]”h"]”h$]”h&]”h±h²uh1j/  hŸh³h Kohj5  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1hìhj2  hžhhŸh³h Nubhí)”}”(hŒ(Install the kernel on the test machine.
”h]”hÊ)”}”(hŒ'Install the kernel on the test machine.”h]”hŒ'Install the kernel on the test machine.”…””}”(hj{  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h Kqhjw  ubah}”(h]”h ]”h"]”h$]”h&]”uh1hìhj2  hžhhŸh³h Nubhí)”}”(hXå  Run the load tests. The '-c' option in perf specifies the sample
event period. We suggest using a suitable prime number, like 500009,
for this purpose.

- For Intel platforms::

   $ perf record -e BR_INST_RETIRED.NEAR_TAKEN:k -a -N -b -c <count> -o <perf_file> -- <loadtest>

- For AMD platforms::

   $ perf record --pfm-event RETIRED_TAKEN_BRANCH_INSTRUCTIONS:k -a -N -b -c <count> -o <perf_file> -- <loadtest>

Note you can repeat the above steps to collect multiple <perf_file>s.
”h]”(hÊ)”}”(hŒ—Run the load tests. The '-c' option in perf specifies the sample
event period. We suggest using a suitable prime number, like 500009,
for this purpose.”h]”hŒ›Run the load tests. The â€˜-câ€™ option in perf specifies the sample
event period. We suggest using a suitable prime number, like 500009,
for this purpose.”…””}”(hj“  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h Kshj  ubjg  )”}”(hhh]”(hí)”}”(hŒwFor Intel platforms::

 $ perf record -e BR_INST_RETIRED.NEAR_TAKEN:k -a -N -b -c <count> -o <perf_file> -- <loadtest>
”h]”(hÊ)”}”(hŒFor Intel platforms::”h]”hŒFor Intel platforms:”…””}”(hj¨  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h Kwhj¤  ubj0  )”}”(hŒ^$ perf record -e BR_INST_RETIRED.NEAR_TAKEN:k -a -N -b -c <count> -o <perf_file> -- <loadtest>”h]”hŒ^$ perf record -e BR_INST_RETIRED.NEAR_TAKEN:k -a -N -b -c <count> -o <perf_file> -- <loadtest>”…””}”hj¶  sbah}”(h]”h ]”h"]”h$]”h&]”h±h²uh1j/  hŸh³h Kyhj¤  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1hìhj¡  ubhí)”}”(hŒ…For AMD platforms::

 $ perf record --pfm-event RETIRED_TAKEN_BRANCH_INSTRUCTIONS:k -a -N -b -c <count> -o <perf_file> -- <loadtest>
”h]”(hÊ)”}”(hŒFor AMD platforms::”h]”hŒFor AMD platforms:”…””}”(hjÎ  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h K{hjÊ  ubj0  )”}”(hŒn$ perf record --pfm-event RETIRED_TAKEN_BRANCH_INSTRUCTIONS:k -a -N -b -c <count> -o <perf_file> -- <loadtest>”h]”hŒn$ perf record --pfm-event RETIRED_TAKEN_BRANCH_INSTRUCTIONS:k -a -N -b -c <count> -o <perf_file> -- <loadtest>”…””}”hjÜ  sbah}”(h]”h ]”h"]”h$]”h&]”h±h²uh1j/  hŸh³h K}hjÊ  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1hìhj¡  ubeh}”(h]”h ]”h"]”h$]”h&]”j	  j
  uh1jf  hŸh³h Kwhj  ubhÊ)”}”(hŒENote you can repeat the above steps to collect multiple <perf_file>s.”h]”hŒENote you can repeat the above steps to collect multiple <perf_file>s.”…””}”(hjö  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h Khj  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1hìhj2  hžhhŸh³h Nubhí)”}”(hŒ>(Optional) Download the raw perf file(s) to the host machine.
”h]”hÊ)”}”(hŒ=(Optional) Download the raw perf file(s) to the host machine.”h]”hŒ=(Optional) Download the raw perf file(s) to the host machine.”…””}”(hj  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h Khj
  ubah}”(h]”h ]”h"]”h$]”h&]”uh1hìhj2  hžhhŸh³h Nubhí)”}”(hXB  Use the create_llvm_prof tool (https://github.com/google/autofdo) to
generate Propeller profile. ::

   $ create_llvm_prof --binary=<vmlinux> --profile=<perf_file>
                      --format=propeller --propeller_output_module_name
                      --out=<propeller_profile_prefix>_cc_profile.txt
                      --propeller_symorder=<propeller_profile_prefix>_ld_profile.txt

"<propeller_profile_prefix>" can be something like "/home/user/dir/any_string".

This command generates a pair of Propeller profiles:
"<propeller_profile_prefix>_cc_profile.txt" and
"<propeller_profile_prefix>_ld_profile.txt".

If there are more than 1 perf_file collected in the previous step,
you can create a temp list file "<perf_file_list>" with each line
containing one perf file name and run::

   $ create_llvm_prof --binary=<vmlinux> --profile=@<perf_file_list>
                      --format=propeller --propeller_output_module_name
                      --out=<propeller_profile_prefix>_cc_profile.txt
                      --propeller_symorder=<propeller_profile_prefix>_ld_profile.txt
”h]”(hÊ)”}”(hŒcUse the create_llvm_prof tool (https://github.com/google/autofdo) to
generate Propeller profile. ::”h]”(hŒUse the create_llvm_prof tool (”…””}”(hj&  hžhhŸNh NubjC  )”}”(hŒ!https://github.com/google/autofdo”h]”hŒ!https://github.com/google/autofdo”…””}”(hj.  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”Œrefuri”j0  uh1jB  hj&  ubhŒ ) to
generate Propeller profile.”…””}”(hj&  hžhhŸNh Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h Kƒhj"  ubj0  )”}”(hX  $ create_llvm_prof --binary=<vmlinux> --profile=<perf_file>
                   --format=propeller --propeller_output_module_name
                   --out=<propeller_profile_prefix>_cc_profile.txt
                   --propeller_symorder=<propeller_profile_prefix>_ld_profile.txt”h]”hX  $ create_llvm_prof --binary=<vmlinux> --profile=<perf_file>
                   --format=propeller --propeller_output_module_name
                   --out=<propeller_profile_prefix>_cc_profile.txt
                   --propeller_symorder=<propeller_profile_prefix>_ld_profile.txt”…””}”hjG  sbah}”(h]”h ]”h"]”h$]”h&]”h±h²uh1j/  hŸh³h K†hj"  ubhÊ)”}”(hŒO"<propeller_profile_prefix>" can be something like "/home/user/dir/any_string".”h]”hŒWâ€œ<propeller_profile_prefix>â€ can be something like â€œ/home/user/dir/any_stringâ€.”…””}”(hjU  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h K‹hj"  ubhÊ)”}”(hŒ‘This command generates a pair of Propeller profiles:
"<propeller_profile_prefix>_cc_profile.txt" and
"<propeller_profile_prefix>_ld_profile.txt".”h]”hŒ™This command generates a pair of Propeller profiles:
â€œ<propeller_profile_prefix>_cc_profile.txtâ€ and
â€œ<propeller_profile_prefix>_ld_profile.txtâ€.”…””}”(hjc  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h Khj"  ubhÊ)”}”(hŒ¬If there are more than 1 perf_file collected in the previous step,
you can create a temp list file "<perf_file_list>" with each line
containing one perf file name and run::”h]”hŒ¯If there are more than 1 perf_file collected in the previous step,
you can create a temp list file â€œ<perf_file_list>â€ with each line
containing one perf file name and run:”…””}”(hjq  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h K‘hj"  ubj0  )”}”(hX  $ create_llvm_prof --binary=<vmlinux> --profile=@<perf_file_list>
                   --format=propeller --propeller_output_module_name
                   --out=<propeller_profile_prefix>_cc_profile.txt
                   --propeller_symorder=<propeller_profile_prefix>_ld_profile.txt”h]”hX  $ create_llvm_prof --binary=<vmlinux> --profile=@<perf_file_list>
                   --format=propeller --propeller_output_module_name
                   --out=<propeller_profile_prefix>_cc_profile.txt
                   --propeller_symorder=<propeller_profile_prefix>_ld_profile.txt”…””}”hj  sbah}”(h]”h ]”h"]”h$]”h&]”h±h²uh1j/  hŸh³h K•hj"  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1hìhj2  hžhhŸh³h Nubhí)”}”(hŒïRebuild the kernel using the AutoFDO and Propeller
profiles. ::

   CONFIG_AUTOFDO_CLANG=y
   CONFIG_PROPELLER_CLANG=y

and ::

   $ make LLVM=1 CLANG_AUTOFDO_PROFILE=<profile_file> CLANG_PROPELLER_PROFILE_PREFIX=<propeller_profile_prefix>”h]”(hÊ)”}”(hŒ?Rebuild the kernel using the AutoFDO and Propeller
profiles. ::”h]”hŒ<Rebuild the kernel using the AutoFDO and Propeller
profiles.”…””}”(hj—  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h Kšhj“  ubj0  )”}”(hŒ/CONFIG_AUTOFDO_CLANG=y
CONFIG_PROPELLER_CLANG=y”h]”hŒ/CONFIG_AUTOFDO_CLANG=y
CONFIG_PROPELLER_CLANG=y”…””}”hj¥  sbah}”(h]”h ]”h"]”h$]”h&]”h±h²uh1j/  hŸh³h Khj“  ubhÊ)”}”(hŒand ::”h]”hŒand”…””}”(hj³  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h K hj“  ubj0  )”}”(hŒl$ make LLVM=1 CLANG_AUTOFDO_PROFILE=<profile_file> CLANG_PROPELLER_PROFILE_PREFIX=<propeller_profile_prefix>”h]”hŒl$ make LLVM=1 CLANG_AUTOFDO_PROFILE=<profile_file> CLANG_PROPELLER_PROFILE_PREFIX=<propeller_profile_prefix>”…””}”hjÁ  sbah}”(h]”h ]”h"]”h$]”h&]”h±h²uh1j/  hŸh³h K¢hj“  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1hìhj2  hžhhŸh³h Nubeh}”(h]”h ]”h"]”h$]”h&]”j|  j}  j~  hj  Œ)”uh1hçhj  hžhhŸh³h Kfubeh}”(h]”Œworkflow”ah ]”h"]”Œworkflow”ah$]”h&]”uh1h´hh¶hžhhŸh³h Kbubeh}”(h]”Œ%using-propeller-with-the-linux-kernel”ah ]”h"]”Œ%using propeller with the linux kernel”ah$]”h&]”uh1h´hhhžhhŸh³h Kubeh}”(h]”h ]”h"]”h$]”h&]”Œsource”h³uh1hŒcurrent_source”NŒcurrent_line”NŒsettings”Œdocutils.frontend”ŒValues”“”)”}”(h¹NŒ	generator”NŒ	datestamp”NŒsource_link”NŒ
source_url”NŒtoc_backlinks”Œentry”Œfootnote_backlinks”KŒsectnum_xform”KŒstrip_comments”NŒstrip_elements_with_classes”NŒstrip_classes”NŒreport_level”KŒ
halt_level”KŒexit_status_level”KŒdebug”NŒwarning_stream”NŒ	traceback”ˆŒinput_encoding”Œ	utf-8-sig”Œinput_encoding_error_handler”Œstrict”Œoutput_encoding”Œutf-8”Œoutput_encoding_error_handler”j  Œerror_encoding”Œutf-8”Œerror_encoding_error_handler”Œbackslashreplace”Œlanguage_code”Œen”Œrecord_dependencies”NŒconfig”NŒ	id_prefix”hŒauto_id_prefix”Œid”Œdump_settings”NŒdump_internals”NŒdump_transforms”NŒdump_pseudo_xml”NŒexpose_internals”NŒstrict_visitor”NŒ_disable_config”NŒ_source”h³Œ_destination”NŒ_config_files”]”Œ7/var/lib/git/docbuild/linux/Documentation/docutils.conf”aŒfile_insertion_enabled”ˆŒraw_enabled”KŒline_length_limit”M'Œpep_references”NŒpep_base_url”Œhttps://peps.python.org/”Œpep_file_url_template”Œpep-%04d”Œrfc_references”NŒrfc_base_url”Œ&https://datatracker.ietf.org/doc/html/”Œ	tab_width”KŒtrim_footnote_reference_space”‰Œsyntax_highlight”Œlong”Œsmart_quotes”ˆŒsmartquotes_locales”]”Œcharacter_level_inline_markup”‰Œdoctitle_xform”‰Œdocinfo_xform”KŒsectsubtitle_xform”‰Œimage_loading”Œlink”Œembed_stylesheet”‰Œcloak_email_addresses”ˆŒsection_self_link”‰Œenv”NubŒreporter”NŒindirect_targets”]”Œsubstitution_defs”}”Œsubstitution_names”}”Œrefnames”}”Œrefids”}”Œnameids”}”(jé  jæ  jD  jA  j  j  já  jÞ  uŒ	nametypes”}”(jé  ‰jD  ‰j  ‰já  ‰uh}”(jæ  h¶jA  j  j  jG  jÞ  j  uŒfootnote_refs”}”Œcitation_refs”}”Œautofootnotes”]”Œautofootnote_refs”]”Œsymbol_footnotes”]”Œsymbol_footnote_refs”]”Œ	footnotes”]”Œ	citations”]”Œautofootnote_start”KŒsymbol_footnote_start”K Œ
id_counter”Œcollections”ŒCounter”“”}”…”R”Œparse_messages”]”Œtransform_messages”]”Œtransformer”NŒinclude_log”]”Œ
decoration”Nhžhub.