From 34184b071817b4f9edbfd1aa2225c196f05a0947 Mon Sep 17 00:00:00 2001 From: "Emilio G. Cota" Date: Wed, 19 Jul 2017 14:32:24 -0400 Subject: tcg: allocate optimizer temps with tcg_malloc Groundwork for supporting multiple TCG contexts. While at it, also allocate temps_used directly as a bitmap of the required size, instead of using a bitmap of TCG_MAX_TEMPS via TCGTempSet. Performance-wise we lose about 1.12% in a translation-heavy workload such as booting+shutting down debian-arm: Performance counter stats for 'taskset -c 0 arm-softmmu/qemu-system-arm \ -machine type=virt -nographic -smp 1 -m 4096 \ -netdev user,id=unet,hostfwd=tcp::2222-:22 \ -device virtio-net-device,netdev=unet \ -drive file=die-on-boot.qcow2,id=myblock,index=0,if=none \ -device virtio-blk-device,drive=myblock \ -kernel kernel.img -append console=ttyAMA0 root=/dev/vda1 \ -name arm,debug-threads=on -smp 1' (10 runs): exec time (s) Relative slowdown wrt original (%) --------------------------------------------------------------- original 20.213321616 0. tcg_malloc 20.441130078 1.1270214 TCGContext 20.477846517 1.3086662 g_malloc 20.780527895 2.8061013 The other two alternatives shown in the table are: - TCGContext: embed temps[TCG_MAX_TEMPS] and TCGTempSet used_temps in TCGContext. This is simple enough but it isn't faster than using tcg_malloc; moreover, it wastes memory. - g_malloc: allocate/deallocate both temps and used_temps every time tcg_optimize is executed. Suggested-by: Richard Henderson Signed-off-by: Emilio G. Cota Signed-off-by: Richard Henderson --- tcg/optimize.c | 42 +++++++++++++++++++----------------------- 1 file changed, 19 insertions(+), 23 deletions(-) diff --git a/tcg/optimize.c b/tcg/optimize.c index 66daced167..438321c6cc 100644 --- a/tcg/optimize.c +++ b/tcg/optimize.c @@ -40,9 +40,6 @@ struct tcg_temp_info { tcg_target_ulong mask; }; -static struct tcg_temp_info temps[TCG_MAX_TEMPS]; -static TCGTempSet temps_used; - static inline struct tcg_temp_info *ts_info(TCGTemp *ts) { return ts->state_ptr; @@ -88,31 +85,27 @@ static void reset_temp(TCGArg arg) reset_ts(arg_temp(arg)); } -/* Reset all temporaries, given that there are NB_TEMPS of them. */ -static void reset_all_temps(int nb_temps) -{ - bitmap_zero(temps_used.l, nb_temps); -} - /* Initialize and activate a temporary. */ -static void init_ts_info(TCGTemp *ts) +static void init_ts_info(struct tcg_temp_info *infos, + TCGTempSet *temps_used, TCGTemp *ts) { size_t idx = temp_idx(ts); - if (!test_bit(idx, temps_used.l)) { - struct tcg_temp_info *ti = &temps[idx]; + if (!test_bit(idx, temps_used->l)) { + struct tcg_temp_info *ti = &infos[idx]; ts->state_ptr = ti; ti->next_copy = ts; ti->prev_copy = ts; ti->is_const = false; ti->mask = -1; - set_bit(idx, temps_used.l); + set_bit(idx, temps_used->l); } } -static void init_arg_info(TCGArg arg) +static void init_arg_info(struct tcg_temp_info *infos, + TCGTempSet *temps_used, TCGArg arg) { - init_ts_info(arg_temp(arg)); + init_ts_info(infos, temps_used, arg_temp(arg)); } static int op_bits(TCGOpcode op) @@ -611,6 +604,8 @@ void tcg_optimize(TCGContext *s) { int oi, oi_next, nb_temps, nb_globals; TCGOp *prev_mb = NULL; + struct tcg_temp_info *infos; + TCGTempSet temps_used; /* Array VALS has an element for each temp. If this temp holds a constant then its value is kept in VALS' element. @@ -619,7 +614,8 @@ void tcg_optimize(TCGContext *s) nb_temps = s->nb_temps; nb_globals = s->nb_globals; - reset_all_temps(nb_temps); + bitmap_zero(temps_used.l, nb_temps); + infos = tcg_malloc(sizeof(struct tcg_temp_info) * nb_temps); for (oi = s->gen_op_buf[0].next; oi != 0; oi = oi_next) { tcg_target_ulong mask, partmask, affected; @@ -640,14 +636,14 @@ void tcg_optimize(TCGContext *s) for (i = 0; i < nb_oargs + nb_iargs; i++) { TCGTemp *ts = arg_temp(op->args[i]); if (ts) { - init_ts_info(ts); + init_ts_info(infos, &temps_used, ts); } } } else { nb_oargs = def->nb_oargs; nb_iargs = def->nb_iargs; for (i = 0; i < nb_oargs + nb_iargs; i++) { - init_arg_info(op->args[i]); + init_arg_info(infos, &temps_used, op->args[i]); } } @@ -1208,7 +1204,7 @@ void tcg_optimize(TCGContext *s) op->args[1], op->args[2]); if (tmp != 2) { if (tmp) { - reset_all_temps(nb_temps); + bitmap_zero(temps_used.l, nb_temps); op->opc = INDEX_op_br; op->args[0] = op->args[3]; } else { @@ -1297,7 +1293,7 @@ void tcg_optimize(TCGContext *s) if (tmp != 2) { if (tmp) { do_brcond_true: - reset_all_temps(nb_temps); + bitmap_zero(temps_used.l, nb_temps); op->opc = INDEX_op_br; op->args[0] = op->args[5]; } else { @@ -1313,7 +1309,7 @@ void tcg_optimize(TCGContext *s) /* Simplify LT/GE comparisons vs zero to a single compare vs the high word of the input. */ do_brcond_high: - reset_all_temps(nb_temps); + bitmap_zero(temps_used.l, nb_temps); op->opc = INDEX_op_brcond_i32; op->args[0] = op->args[1]; op->args[1] = op->args[3]; @@ -1339,7 +1335,7 @@ void tcg_optimize(TCGContext *s) goto do_default; } do_brcond_low: - reset_all_temps(nb_temps); + bitmap_zero(temps_used.l, nb_temps); op->opc = INDEX_op_brcond_i32; op->args[1] = op->args[2]; op->args[2] = op->args[4]; @@ -1459,7 +1455,7 @@ void tcg_optimize(TCGContext *s) block, otherwise we only trash the output args. "mask" is the non-zero bits mask for the first output arg. */ if (def->flags & TCG_OPF_BB_END) { - reset_all_temps(nb_temps); + bitmap_zero(temps_used.l, nb_temps); } else { do_reset_output: for (i = 0; i < nb_oargs; i++) { -- cgit v1.2.1