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Diffstat (limited to 'docs/devel/tcg-plugins.rst')
| -rw-r--r-- | docs/devel/tcg-plugins.rst | 86 |
1 files changed, 85 insertions, 1 deletions
diff --git a/docs/devel/tcg-plugins.rst b/docs/devel/tcg-plugins.rst index 18c6581d85..7e54f12837 100644 --- a/docs/devel/tcg-plugins.rst +++ b/docs/devel/tcg-plugins.rst @@ -71,7 +71,8 @@ API Usage ===== -The QEMU binary needs to be compiled for plugin support:: +Any QEMU binary with TCG support has plugins enabled by default. +Earlier releases needed to be explicitly enabled with:: configure --enable-plugins @@ -319,3 +320,86 @@ the user to see what hardware is accessed how often. It has a number of options: off:0000001c, 1, 2 off:00000020, 1, 2 ... + +- contrib/plugins/execlog.c + +The execlog tool traces executed instructions with memory access. It can be used +for debugging and security analysis purposes. +Please be aware that this will generate a lot of output. + +The plugin takes no argument:: + + qemu-system-arm $(QEMU_ARGS) \ + -plugin ./contrib/plugins/libexeclog.so -d plugin + +which will output an execution trace following this structure:: + + # vCPU, vAddr, opcode, disassembly[, load/store, memory addr, device]... + 0, 0xa12, 0xf8012400, "movs r4, #0" + 0, 0xa14, 0xf87f42b4, "cmp r4, r6" + 0, 0xa16, 0xd206, "bhs #0xa26" + 0, 0xa18, 0xfff94803, "ldr r0, [pc, #0xc]", load, 0x00010a28, RAM + 0, 0xa1a, 0xf989f000, "bl #0xd30" + 0, 0xd30, 0xfff9b510, "push {r4, lr}", store, 0x20003ee0, RAM, store, 0x20003ee4, RAM + 0, 0xd32, 0xf9893014, "adds r0, #0x14" + 0, 0xd34, 0xf9c8f000, "bl #0x10c8" + 0, 0x10c8, 0xfff96c43, "ldr r3, [r0, #0x44]", load, 0x200000e4, RAM + +- contrib/plugins/cache + +Cache modelling plugin that measures the performance of a given cache +configuration when a given working set is run:: + + qemu-x86_64 -plugin ./contrib/plugins/libcache.so \ + -d plugin -D cache.log ./tests/tcg/x86_64-linux-user/float_convs + +will report the following:: + + Data accesses: 996479, Misses: 507 + Miss rate: 0.050879% + + Instruction accesses: 2641737, Misses: 18617 + Miss rate: 0.704726% + + address, data misses, instruction + 0x424f1e (_int_malloc), 109, movq %rax, 8(%rcx) + 0x41f395 (_IO_default_xsputn), 49, movb %dl, (%rdi, %rax) + 0x42584d (ptmalloc_init.part.0), 33, movaps %xmm0, (%rax) + 0x454d48 (__tunables_init), 20, cmpb $0, (%r8) + ... + + address, fetch misses, instruction + 0x4160a0 (__vfprintf_internal), 744, movl $1, %ebx + 0x41f0a0 (_IO_setb), 744, endbr64 + 0x415882 (__vfprintf_internal), 744, movq %r12, %rdi + 0x4268a0 (__malloc), 696, andq $0xfffffffffffffff0, %rax + ... + +The plugin has a number of arguments, all of them are optional: + + * arg="limit=N" + + Print top N icache and dcache thrashing instructions along with their + address, number of misses, and its disassembly. (default: 32) + + * arg="icachesize=N" + * arg="iblksize=B" + * arg="iassoc=A" + + Instruction cache configuration arguments. They specify the cache size, block + size, and associativity of the instruction cache, respectively. + (default: N = 16384, B = 64, A = 8) + + * arg="dcachesize=N" + * arg="dblksize=B" + * arg="dassoc=A" + + Data cache configuration arguments. They specify the cache size, block size, + and associativity of the data cache, respectively. + (default: N = 16384, B = 64, A = 8) + + * arg="evict=POLICY" + + Sets the eviction policy to POLICY. Available policies are: :code:`lru`, + :code:`fifo`, and :code:`rand`. The plugin will use the specified policy for + both instruction and data caches. (default: POLICY = :code:`lru`) |