On Mon, 3 Jun 2019 at 21:36, Christophe Lyon <christophe.l...@linaro.org> wrote: > > On Thu, 30 May 2019 at 12:28, Alex Bennée <alex.ben...@linaro.org> wrote: > > > > > > Hi, > > > > Food for thought for today's sync up. I've been writting QEMU plugins to > > exercise the plugin system and see what sort of useful information you > > can extract when you can control the instruction stream. > > > > For example I now have a plugin that can break down instruction counts > > for any given run, for example a kernel boot: > > > > Instruction Classes: > > Class: UDEF not counted > > Class: SVE (68 hits) > > Class: Reserved (0 hits) > > Class: PCrel addr (4589078 hits) > > Class: Add/Sub (imm,tags) (0 hits) > > Class: Add/Sub (imm) (26832113 hits) > > Class: Logical (imm) (74304974 hits) > > Class: Move Wide (imm) (10933759 hits) > > Class: Bitfield (71470957 hits) > > Class: Extract (85655 hits) > > Class: Data Proc Imm (0 hits) > > Class: Cond Branch (imm) (37227632 hits) > > Class: Exception Gen (6 hits) > > Class: NOP not counted > > Class: Hints (244825554 hits) > > Class: Barriers (1668558 hits) > > Class: PSTATE (202144 hits) > > Class: System Insn (7132992 hits) > > Class: System Reg (2268308 hits) > > Class: Branch (reg) (6280976 hits) > > Class: Branch (imm) (18347905 hits) > > Class: Cmp & Branch (180167025 hits) > > Class: Tst & Branch (4092972 hits) > > Class: Branches (0 hits) > > Class: AdvSimd ldstmult (0 hits) > > Class: AdvSimd ldstmult++ (0 hits) > > Class: AdvSimd ldst (0 hits) > > Class: AdvSimd ldst++ (0 hits) > > Class: ldst excl (160861365 hits) > > Class: Prefetch (0 hits) > > Class: Load Reg (lit) (12828544 hits) > > Class: ldst noalloc pair (0 hits) > > Class: ldst pair (60381349 hits) > > Class: ldst reg (0 hits) > > Class: Atomic ldst (0 hits) > > Class: ldst reg (reg off) (0 hits) > > Class: ldst reg (pac) (0 hits) > > Class: ldst reg (imm) (119597941 hits) > > Class: Loads & Stores (0 hits) > > Class: Data Proc Reg (113586343 hits) > > Class: Scalar FP (0 hits) > > Class: Unclassified (0 hits) > > > > You can break down each class to individual instructions. For example > > the Hints are mostly: > > > > Individual Instructions: > > Instr: wfe (132400072 hits) (op=0xd503205f/ > > Hints) > > Instr: sevl (66433640 hits) (op=0xd50320bf/ Hints) > > Instr: yield (29619246 hits) (op=0xd503203f/ Hints) > > Instr: wfi (2865 hits) (op=0xd503207f/ Hints) > > > > So I'm looking for a similar experiment that would be useful for the > > memory sub-system. When I chatted to Maxim we thought maybe a simplified > > cache line simulator might be useful. The aim wouldn't be to simulate > > what a real cache might do but to be useful say for identifying regions > > of code which might be susceptible to cache line bouncing. So as > > compiler writers what sort of run time memory behaviour would you like > > to track? What sort of information would be useful to extract with such > > a tool? > > > > I'm open to ideas ;-) > > > > On our side (ST), we use qemu plugins for various things: > - code coverage > - code profiling > - loop analysis (more compiler developer oriented than the previous ones) >
Actually for more detailed info you can have a look at: Example plugins reference: https://github.com/atos-tools/qemu/tree/stable-3.1.plugins/tcg/plugins I.e. example plugins list: - Full instruction trace - DineroIV cache simulator - Instruction group/mnemonic dynamic count - coverage - per-function profile - oprofile - function call stack - global instruction count - I/O memory mapped simulation - block trace Other more advanced plugins (ref for instance paper: https://ppopp19.sigplan.org/details/PPoPP-2019-papers/9/Data-Flow-Dependence-Profiling-for-Structured-Transformations): - Function call graph, CFGs and function call-stack sampling (flamegraph) - Dynamic Dependence Graph > Christophe > > > > > -- > > Alex Bennée > > _______________________________________________ > > linaro-toolchain mailing list > > linaro-toolchain@lists.linaro.org > > https://lists.linaro.org/mailman/listinfo/linaro-toolchain _______________________________________________ linaro-toolchain mailing list linaro-toolchain@lists.linaro.org https://lists.linaro.org/mailman/listinfo/linaro-toolchain
