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a="841047527" X-IronPort-AV: E=Sophos;i="6.01,165,1684825200"; d="scan'208";a="841047527" Received: from wufei-optiplex-7090.sh.intel.com ([10.238.200.247]) by orsmga004.jf.intel.com with ESMTP; 28 Jun 2023 05:02:32 -0700 From: Fei Wu To: richard.henderson@linaro.org, alex.bennee@linaro.org, qemu-devel@nongnu.org Cc: Fei Wu , Paolo Bonzini Subject: [PATCH v16 9/9] docs: add tb-stats how to Date: Wed, 28 Jun 2023 20:04:30 +0800 Message-Id: <20230628120430.73777-10-fei2.wu@intel.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20230628120430.73777-1-fei2.wu@intel.com> References: <20230628120430.73777-1-fei2.wu@intel.com> MIME-Version: 1.0 Received-SPF: pass client-ip=192.55.52.88; envelope-from=fei2.wu@intel.com; helo=mga01.intel.com X-Spam_score_int: -43 X-Spam_score: -4.4 X-Spam_bar: ---- X-Spam_report: (-4.4 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Signed-off-by: Fei Wu --- docs/devel/index-tcg.rst | 1 + docs/devel/tcg-tbstats.rst | 126 +++++++++++++++++++++++++++++++++++++ 2 files changed, 127 insertions(+) create mode 100644 docs/devel/tcg-tbstats.rst diff --git a/docs/devel/index-tcg.rst b/docs/devel/index-tcg.rst index b44ff8b5a4..8d2832737f 100644 --- a/docs/devel/index-tcg.rst +++ b/docs/devel/index-tcg.rst @@ -14,4 +14,5 @@ are only implementing things for HW accelerated hypervisors. multi-thread-tcg tcg-icount tcg-plugins + tcg-tbstats replay diff --git a/docs/devel/tcg-tbstats.rst b/docs/devel/tcg-tbstats.rst new file mode 100644 index 0000000000..3940a3cb9d --- /dev/null +++ b/docs/devel/tcg-tbstats.rst @@ -0,0 +1,126 @@ +============ +TBStatistics +============ + +What is TBStatistics +==================== + +TBStatistics (tb_stats) is a tool to gather various internal information of TCG +during binary translation, this allows us to identify such as hottest TBs, +guest to host instruction translation ratio, number of spills during register +allocation and more. + +What does TBStatistics collect +=============================== + +TBStatistics mainly collects the following stats: + +* TB exec stats, e.g. the execution count of each TB +* TB jit stats, e.g. guest insn count, tcg ops, tcg spill etc. +* opcount of each instruction, use 'info opcount' to show it + + +How to use TBStatistics +======================= + +1. HMP interface +---------------- + +TBStatistics provides HMP interface, you can try the following examples after +connecting to the monitor. + +* First check the help info:: + + (qemu) help tb_stats + tb_stats command [flag] -- Control tb statistics collection:tb_stats (start|stop|status) [all|jit|exec] + + (qemu) help info tb-list + info tb-list [number sortedby] -- show a [number] translated blocks sorted by [sortedby]sortedby opts: hotness hg spills + + (qemu) help info tb + info tb id [flag1,flag2,...] -- show information about one translated block by id.dump flags can be used to set dump code level: out_asm in_asm op + +* Enable TBStatistics:: + + (qemu) tb_stats start all + (qemu) + +* Get interested TB list:: + + (qemu) info tb-list 2 + TB id:0 | phys:0x79bca0 virt:0xffffffff8059bca0 flags:0x01024001 0 inv/1 + | exec:1464084/0 guest inst cov:0.15% + | trans:1 inst: g:3 op:16 op_opt:15 spills:0 + | h/g (host bytes / guest insts): 64.000000 + + TB id:1 | phys:0x2adf0c virt:0xffffffff800adf0c flags:0x01024001 0 inv/1 + | exec:1033298/0 guest inst cov:0.28% + | trans:1 inst: g:8 op:35 op_opt:33 spills:0 + | h/g (host bytes / guest insts): 86.000000 + +* Dive into the specific TB:: + + (qemu) info tb 0 + ------------------------------ + + TB id:0 | phys:0x63474e virt:0x0000000000000000 flags:0x01028001 0 inv/1 + | exec:131719290/0 guest inst cov:8.44% + | trans:1 ints: g:9 op:36 op_opt:34 spills:0 + | h/g (host bytes / guest insts): 51.555557 + + 0x0063474e: 00194a83 lbu s5,1(s2) + 0x00634752: 00094803 lbu a6,0(s2) + 0x00634756: 0b09 addi s6,s6,2 + 0x00634758: 008a9a9b slliw s5,s5,8 + 0x0063475c: 01586833 or a6,a6,s5 + 0x00634760: ff0b1f23 sh a6,-2(s6) + 0x00634764: 1c7d addi s8,s8,-1 + 0x00634766: 0909 addi s2,s2,2 + 0x00634768: fe0c13e3 bnez s8,-26 # 0x63474e + + ------------------------------ + +* Stop TBStatistics after investigation, this will disable TBStatistics completely.:: + + (qemu) tb_stats stop + (qemu) + +* Definitely, TBStatistics can be restarted for another round of investigation.:: + + (qemu) tb_stats start all + (qemu) + + +2. Start TBStatistics with command line +--------------------------------------- + +If you don't want to missing anything at guest starting, command line option is +provided to start TBStatistics at start::: + + -d tb_stats_{all,jit,exec} + + +3. Dump hottest at exit +----------------------- + +TBStatistics is able to dump hottest TB information at exit as follows::: + + -d tb_stats_{all,jit,exec}[:dump_num_at_exit] + +e.g. starting qemu like this::: + + -d tb_stats_all:2 + +QEMU prints the following at exit::: + + TB id:0 | phys:0x242b8 virt:0x00000000000242b8 flags:0x00024078 0 inv/0 + | exec:1161/0 guest inst cov:10.36% + | trans:1 ints: g:2 op:20 op_opt:19 spills:0 + | h/g (host bytes / guest insts): 61.500000 + + TB id:1 | phys:0x242be virt:0x00000000000242be flags:0x00024078 0 inv/0 + | exec:1161/0 guest inst cov:10.36% + | trans:1 ints: g:2 op:20 op_opt:18 spills:0 + | h/g (host bytes / guest insts): 59.500000 + +This is particularly useful for user mode QEMU.