| Message ID | 20210209182749.31323-8-alex.bennee@linaro.org |
|---|---|
| State | Superseded |
| Headers | show |
| Series | fix plugins double counting with mmio, cleanup CF_ flags | expand |
On 2/9/21 10:27 AM, Alex Bennée wrote: > /* Refill decrementer and continue execution. */ > - insns_left = MIN(0xffff, cpu->icount_budget); > + insns_left = MIN(CF_COUNT_MASK, cpu->icount_budget); ... > + g_assert(insns_left < CF_COUNT_MASK); Why both the MIN and the assert? r~
Richard Henderson <richard.henderson@linaro.org> writes: > On 2/9/21 10:27 AM, Alex Bennée wrote: >> /* Refill decrementer and continue execution. */ >> - insns_left = MIN(0xffff, cpu->icount_budget); >> + insns_left = MIN(CF_COUNT_MASK, cpu->icount_budget); > ... >> + g_assert(insns_left < CF_COUNT_MASK); > > Why both the MIN and the assert? Lack of faith in MIN I guess ;-) I'll drop the assert. > > > r~ -- Alex Bennée
diff --git a/accel/tcg/cpu-exec.c b/accel/tcg/cpu-exec.c index d9ef69121c..7f477af891 100644 --- a/accel/tcg/cpu-exec.c +++ b/accel/tcg/cpu-exec.c @@ -730,16 +730,18 @@ static inline void cpu_loop_exec_tb(CPUState *cpu, TranslationBlock *tb, /* Ensure global icount has gone forward */ icount_update(cpu); /* Refill decrementer and continue execution. */ - insns_left = MIN(0xffff, cpu->icount_budget); + insns_left = MIN(CF_COUNT_MASK, cpu->icount_budget); cpu_neg(cpu)->icount_decr.u16.low = insns_left; cpu->icount_extra = cpu->icount_budget - insns_left; - if (!cpu->icount_extra && insns_left < tb->icount) { - /* Execute any remaining instructions, then let the main loop - * handle the next event. - */ - if (insns_left > 0) { - cpu_exec_nocache(cpu, insns_left, tb, false); - } + + /* + * If the next tb has more instructions than we have left to + * execute we need to ensure we find/generate a TB with exactly + * insns_left instructions in it. + */ + if (!cpu->icount_extra && insns_left > 0 && insns_left < tb->icount) { + g_assert(insns_left < CF_COUNT_MASK); + cpu->cflags_next_tb = (tb->cflags & ~CF_COUNT_MASK) | insns_left; } #endif }
When we exit a block under icount with instructions left to execute we might need a shorter than normal block to take us to the next deterministic event. Instead of creating a throwaway block on demand we use the existing compile flags mechanism to ensure we fetch (or compile and fetch) a block with exactly the number of instructions we need. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> --- accel/tcg/cpu-exec.c | 18 ++++++++++-------- 1 file changed, 10 insertions(+), 8 deletions(-) -- 2.20.1