Alex Bennée <alex.ben...@linaro.org> writes:
> vandersonmr <vanderson...@gmail.com> writes: > >> We want to store statistics for each TB even after flushes. >> We do not want to modify or grow the TB struct. >> So we create a new struct to contain this statistics and >> link it to each TB while they are created. >> >> Signed-off-by: Vanderson M. do Rosario <vanderson...@gmail.com> >> --- >> accel/tcg/translate-all.c | 40 +++++++++++++++++++++++++++++++++++++++ >> include/exec/exec-all.h | 21 ++++++++++++++++++++ >> include/exec/tb-context.h | 1 + >> include/qemu/log.h | 1 + >> 4 files changed, 63 insertions(+) >> >> diff --git a/accel/tcg/translate-all.c b/accel/tcg/translate-all.c >> index 5d1e08b169..f7e99f90e0 100644 >> --- a/accel/tcg/translate-all.c >> +++ b/accel/tcg/translate-all.c >> @@ -1118,6 +1118,18 @@ static inline void code_gen_alloc(size_t tb_size) >> } >> } >> >> +static gint statistics_cmp(gconstpointer p1, gconstpointer p2) >> +{ >> + const TBStatistics *a = (TBStatistics *) p1; >> + const TBStatistics *b = (TBStatistics *) p2; >> + >> + return (a->pc == b->pc && >> + a->cs_base == b->cs_base && >> + a->flags == b->flags && >> + a->page_addr[0] == b->page_addr[0] && >> + a->page_addr[1] == b->page_addr[1]) ? 0 : 1; >> +} >> + > > There are a bunch of white space errors that need fixing up as you > probably already know from patchew ;-) > >> static bool tb_cmp(const void *ap, const void *bp) >> { >> const TranslationBlock *a = ap; >> @@ -1586,6 +1598,29 @@ static inline void tb_page_add(PageDesc *p, >> TranslationBlock *tb, >> #endif >> } >> >> +static void tb_insert_statistics_structure(TranslationBlock *tb) { >> + TBStatistics *new_stats = g_new0(TBStatistics, 1); >> + new_stats->pc = tb->pc; >> + new_stats->cs_base = tb->cs_base; >> + new_stats->flags = tb->flags; >> + new_stats->page_addr[0] = tb->page_addr[0]; >> + new_stats->page_addr[1] = tb->page_addr[1]; >> + >> + GList *lookup_result = g_list_find_custom(tb_ctx.tb_statistics, >> new_stats, statistics_cmp); >> + >> + if (lookup_result) { >> + /* If there is already a TBStatistic for this TB from a >> previous flush >> + * then just make the new TB point to the older TBStatistic >> + */ >> + free(new_stats); >> + tb->tb_stats = lookup_result->data; >> + } else { >> + /* If not, then points to the new tb_statistics and add it to >> the hash */ >> + tb->tb_stats = new_stats; >> + tb_ctx.tb_statistics = g_list_prepend(tb_ctx.tb_statistics, >> new_stats); > > This is going to race as nothing prevents two threads attempting to > insert records at the same time. > >> + } >> +} >> + >> /* add a new TB and link it to the physical page tables. phys_page2 is >> * (-1) to indicate that only one page contains the TB. >> * >> @@ -1636,6 +1671,11 @@ tb_link_page(TranslationBlock *tb, tb_page_addr_t >> phys_pc, >> void *existing_tb = NULL; >> uint32_t h; >> >> + if (qemu_loglevel_mask(CPU_LOG_HOT_TBS)) { >> + /* create and link to its TB a structure to store statistics */ >> + tb_insert_statistics_structure(tb); >> + } >> + >> /* add in the hash table */ >> h = tb_hash_func(phys_pc, tb->pc, tb->flags, tb->cflags & >> CF_HASH_MASK, >> tb->trace_vcpu_dstate); > > Perhaps we could just have a second qht array which allows for > "unlocked" insertion of record. You could take advantage of the fact the > hash would be the same: > > h = tb_hash_func(phys_pc, tb->pc, tb->flags, tb->cflags & > CF_HASH_MASK, > tb->trace_vcpu_dstate); > qht_insert(&tb_ctx.htable, tb, h, &existing_tb); > > /* remove TB from the page(s) if we couldn't insert it */ > if (unlikely(existing_tb)) { > ... > tb = existing_tb; > } else if (qemu_loglevel_mask(CPU_LOG_HOT_TBS)) { > TBStatistics *new_stats = g_new0(TBStatistics, 1); > bool ok; > new_stats->pc = tb->pc; > new_stats->cs_base = tb->cs_base; > new_stats->flags = tb->flags; > new_stats->page_addr[0] = tb->page_addr[0]; > new_stats->page_addr[1] = tb->page_addr[1]; > ok = qht_insert(&tb_ctx.tb_stats, new_stats, h, NULL); > /* > * This should never fail as we succeeded in inserting the > * TB itself which means we haven't seen this combination yet. > */ > g_assert(ok); > } > > It would also avoid the clunkiness of having to allocate and then > freeing an unused structure. Actually thinking on this we still have to handle it. We may have tb_flushed away a translation and just be regenerating the same block. As TBStatistics should transcend tb_flush events we need to re-use it's structure. It would be worth counting the regens as well so we can see blocks that keep getting re-translated after each flush. > >> diff --git a/include/exec/exec-all.h b/include/exec/exec-all.h >> index 16034ee651..359100ef3b 100644 >> --- a/include/exec/exec-all.h >> +++ b/include/exec/exec-all.h >> @@ -324,6 +324,24 @@ static inline void >> tlb_flush_by_mmuidx_all_cpus_synced(CPUState *cpu, >> #define CODE_GEN_AVG_BLOCK_SIZE 150 >> #endif >> >> +typedef struct TBStatistics TBStatistics; >> + >> +/* >> + * This struct stores statistics such as execution count of the >> TranslationBlocks. >> + * Each TB has its own TBStatistics. TBStatistics is suppose to live even >> after >> + * flushes. >> + */ >> +struct TBStatistics { >> + target_ulong pc; >> + target_ulong cs_base; >> + uint32_t flags; >> + tb_page_addr_t page_addr[2]; >> + >> + // total number of times that the related TB have being executed > > No c++ style comments > >> + uint32_t exec_count; >> + uint32_t exec_count_overflows; >> +}; >> + >> /* >> * Translation Cache-related fields of a TB. >> * This struct exists just for convenience; we keep track of TB's in a >> binary >> @@ -403,6 +421,9 @@ struct TranslationBlock { >> uintptr_t jmp_list_head; >> uintptr_t jmp_list_next[2]; >> uintptr_t jmp_dest[2]; >> + >> + // Pointer to a struct where statistics from the TB is stored > > No c++ style comments > >> + TBStatistics *tb_stats; >> }; >> >> extern bool parallel_cpus; >> diff --git a/include/exec/tb-context.h b/include/exec/tb-context.h >> index feb585e0a7..a78ce92e60 100644 >> --- a/include/exec/tb-context.h >> +++ b/include/exec/tb-context.h >> @@ -35,6 +35,7 @@ struct TBContext { >> >> /* statistics */ >> unsigned tb_flush_count; >> + GList *tb_statistics; >> }; >> >> extern TBContext tb_ctx; >> diff --git a/include/qemu/log.h b/include/qemu/log.h >> index b097a6cae1..2fca65dd01 100644 >> --- a/include/qemu/log.h >> +++ b/include/qemu/log.h >> @@ -45,6 +45,7 @@ static inline bool qemu_log_separate(void) >> /* LOG_TRACE (1 << 15) is defined in log-for-trace.h */ >> #define CPU_LOG_TB_OP_IND (1 << 16) >> #define CPU_LOG_TB_FPU (1 << 17) >> +#define CPU_LOG_HOT_TBS (1 << 18) >> >> /* Lock output for a series of related logs. Since this is not needed >> * for a single qemu_log / qemu_log_mask / qemu_log_mask_and_addr, we -- Alex Bennée