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tcg: distribute profiling counters across TCGContext's
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This is groundwork for supporting multiple TCG contexts.

To avoid scalability issues when profiling info is enabled, this patch
makes the profiling info counters distributed via the following changes:

1) Consolidate profile info into its own struct, TCGProfile, which
   TCGContext also includes. Note that tcg_table_op_count is brought
   into TCGProfile after dropping the tcg_ prefix.
2) Iterate over the TCG contexts in the system to obtain the total counts.

This change also requires updating the accessors to TCGProfile fields to
use atomic_read/set whenever there may be conflicting accesses (as defined
in C11) to them.

Reviewed-by: Richard Henderson <[email protected]>
Signed-off-by: Emilio G. Cota <[email protected]>
Signed-off-by: Richard Henderson <[email protected]>
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@cota @rth7680
cota authored and rth7680 committed Oct 24, 2017
1 parent df2cce2 commit c3fac11
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Showing 3 changed files with 126 additions and 45 deletions.
23 changes: 13 additions & 10 deletions accel/tcg/translate-all.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -310,6 +310,7 @@ static int cpu_restore_state_from_tb(CPUState *cpu, TranslationBlock *tb,
uint8_t *p = tb->tc.ptr + tb->tc.size;
int i, j, num_insns = tb->icount;
#ifdef CONFIG_PROFILER
TCGProfile *prof = &tcg_ctx->prof;
int64_t ti = profile_getclock();
#endif

Expand Down Expand Up @@ -344,8 +345,9 @@ static int cpu_restore_state_from_tb(CPUState *cpu, TranslationBlock *tb,
restore_state_to_opc(env, tb, data);

#ifdef CONFIG_PROFILER
tcg_ctx->restore_time += profile_getclock() - ti;
tcg_ctx->restore_count++;
atomic_set(&prof->restore_time,
prof->restore_time + profile_getclock() - ti);
atomic_set(&prof->restore_count, prof->restore_count + 1);
#endif
return 0;
}
Expand Down Expand Up @@ -1300,6 +1302,7 @@ TranslationBlock *tb_gen_code(CPUState *cpu,
tcg_insn_unit *gen_code_buf;
int gen_code_size, search_size;
#ifdef CONFIG_PROFILER
TCGProfile *prof = &tcg_ctx->prof;
int64_t ti;
#endif
assert_memory_lock();
Expand Down Expand Up @@ -1327,8 +1330,8 @@ TranslationBlock *tb_gen_code(CPUState *cpu,
tcg_ctx->tb_cflags = cflags;

#ifdef CONFIG_PROFILER
tcg_ctx->tb_count1++; /* includes aborted translations because of
exceptions */
/* includes aborted translations because of exceptions */
atomic_set(&prof->tb_count1, prof->tb_count1 + 1);
ti = profile_getclock();
#endif

Expand All @@ -1353,8 +1356,8 @@ TranslationBlock *tb_gen_code(CPUState *cpu,
}

#ifdef CONFIG_PROFILER
tcg_ctx->tb_count++;
tcg_ctx->interm_time += profile_getclock() - ti;
atomic_set(&prof->tb_count, prof->tb_count + 1);
atomic_set(&prof->interm_time, prof->interm_time + profile_getclock() - ti);
ti = profile_getclock();
#endif

Expand All @@ -1374,10 +1377,10 @@ TranslationBlock *tb_gen_code(CPUState *cpu,
tb->tc.size = gen_code_size;

#ifdef CONFIG_PROFILER
tcg_ctx->code_time += profile_getclock() - ti;
tcg_ctx->code_in_len += tb->size;
tcg_ctx->code_out_len += gen_code_size;
tcg_ctx->search_out_len += search_size;
atomic_set(&prof->code_time, prof->code_time + profile_getclock() - ti);
atomic_set(&prof->code_in_len, prof->code_in_len + tb->size);
atomic_set(&prof->code_out_len, prof->code_out_len + gen_code_size);
atomic_set(&prof->search_out_len, prof->search_out_len + search_size);
#endif

#ifdef DEBUG_DISAS
Expand Down
110 changes: 92 additions & 18 deletions tcg/tcg.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1547,7 +1547,7 @@ void tcg_op_remove(TCGContext *s, TCGOp *op)
memset(op, 0, sizeof(*op));

#ifdef CONFIG_PROFILER
s->del_op_count++;
atomic_set(&s->prof.del_op_count, s->prof.del_op_count + 1);
#endif
}

Expand Down Expand Up @@ -2715,15 +2715,79 @@ static void tcg_reg_alloc_call(TCGContext *s, TCGOp *op)

#ifdef CONFIG_PROFILER

static int64_t tcg_table_op_count[NB_OPS];
/* avoid copy/paste errors */
#define PROF_ADD(to, from, field) \
do { \
(to)->field += atomic_read(&((from)->field)); \
} while (0)

#define PROF_MAX(to, from, field) \
do { \
typeof((from)->field) val__ = atomic_read(&((from)->field)); \
if (val__ > (to)->field) { \
(to)->field = val__; \
} \
} while (0)

/* Pass in a zero'ed @prof */
static inline
void tcg_profile_snapshot(TCGProfile *prof, bool counters, bool table)
{
unsigned int i;

for (i = 0; i < n_tcg_ctxs; i++) {
const TCGProfile *orig = &tcg_ctxs[i]->prof;

if (counters) {
PROF_ADD(prof, orig, tb_count1);
PROF_ADD(prof, orig, tb_count);
PROF_ADD(prof, orig, op_count);
PROF_MAX(prof, orig, op_count_max);
PROF_ADD(prof, orig, temp_count);
PROF_MAX(prof, orig, temp_count_max);
PROF_ADD(prof, orig, del_op_count);
PROF_ADD(prof, orig, code_in_len);
PROF_ADD(prof, orig, code_out_len);
PROF_ADD(prof, orig, search_out_len);
PROF_ADD(prof, orig, interm_time);
PROF_ADD(prof, orig, code_time);
PROF_ADD(prof, orig, la_time);
PROF_ADD(prof, orig, opt_time);
PROF_ADD(prof, orig, restore_count);
PROF_ADD(prof, orig, restore_time);
}
if (table) {
int i;

for (i = 0; i < NB_OPS; i++) {
PROF_ADD(prof, orig, table_op_count[i]);
}
}
}
}

#undef PROF_ADD
#undef PROF_MAX

static void tcg_profile_snapshot_counters(TCGProfile *prof)
{
tcg_profile_snapshot(prof, true, false);
}

static void tcg_profile_snapshot_table(TCGProfile *prof)
{
tcg_profile_snapshot(prof, false, true);
}

void tcg_dump_op_count(FILE *f, fprintf_function cpu_fprintf)
{
TCGProfile prof = {};
int i;

tcg_profile_snapshot_table(&prof);
for (i = 0; i < NB_OPS; i++) {
cpu_fprintf(f, "%s %" PRId64 "\n", tcg_op_defs[i].name,
tcg_table_op_count[i]);
prof.table_op_count[i]);
}
}
#else
Expand All @@ -2736,22 +2800,25 @@ void tcg_dump_op_count(FILE *f, fprintf_function cpu_fprintf)

int tcg_gen_code(TCGContext *s, TranslationBlock *tb)
{
#ifdef CONFIG_PROFILER
TCGProfile *prof = &s->prof;
#endif
int i, oi, oi_next, num_insns;

#ifdef CONFIG_PROFILER
{
int n;

n = s->gen_op_buf[0].prev + 1;
s->op_count += n;
if (n > s->op_count_max) {
s->op_count_max = n;
atomic_set(&prof->op_count, prof->op_count + n);
if (n > prof->op_count_max) {
atomic_set(&prof->op_count_max, n);
}

n = s->nb_temps;
s->temp_count += n;
if (n > s->temp_count_max) {
s->temp_count_max = n;
atomic_set(&prof->temp_count, prof->temp_count + n);
if (n > prof->temp_count_max) {
atomic_set(&prof->temp_count_max, n);
}
}
#endif
Expand All @@ -2768,16 +2835,16 @@ int tcg_gen_code(TCGContext *s, TranslationBlock *tb)
#endif

#ifdef CONFIG_PROFILER
s->opt_time -= profile_getclock();
atomic_set(&prof->opt_time, prof->opt_time - profile_getclock());
#endif

#ifdef USE_TCG_OPTIMIZATIONS
tcg_optimize(s);
#endif

#ifdef CONFIG_PROFILER
s->opt_time += profile_getclock();
s->la_time -= profile_getclock();
atomic_set(&prof->opt_time, prof->opt_time + profile_getclock());
atomic_set(&prof->la_time, prof->la_time - profile_getclock());
#endif

liveness_pass_1(s);
Expand All @@ -2801,7 +2868,7 @@ int tcg_gen_code(TCGContext *s, TranslationBlock *tb)
}

#ifdef CONFIG_PROFILER
s->la_time += profile_getclock();
atomic_set(&prof->la_time, prof->la_time + profile_getclock());
#endif

#ifdef DEBUG_DISAS
Expand Down Expand Up @@ -2834,7 +2901,7 @@ int tcg_gen_code(TCGContext *s, TranslationBlock *tb)

oi_next = op->next;
#ifdef CONFIG_PROFILER
tcg_table_op_count[opc]++;
atomic_set(&prof->table_op_count[opc], prof->table_op_count[opc] + 1);
#endif

switch (opc) {
Expand Down Expand Up @@ -2915,10 +2982,17 @@ int tcg_gen_code(TCGContext *s, TranslationBlock *tb)
#ifdef CONFIG_PROFILER
void tcg_dump_info(FILE *f, fprintf_function cpu_fprintf)
{
TCGContext *s = tcg_ctx;
int64_t tb_count = s->tb_count;
int64_t tb_div_count = tb_count ? tb_count : 1;
int64_t tot = s->interm_time + s->code_time;
TCGProfile prof = {};
const TCGProfile *s;
int64_t tb_count;
int64_t tb_div_count;
int64_t tot;

tcg_profile_snapshot_counters(&prof);
s = &prof;
tb_count = s->tb_count;
tb_div_count = tb_count ? tb_count : 1;
tot = s->interm_time + s->code_time;

cpu_fprintf(f, "JIT cycles %" PRId64 " (%0.3f s at 2.4 GHz)\n",
tot, tot / 2.4e9);
Expand Down
38 changes: 21 additions & 17 deletions tcg/tcg.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -599,6 +599,26 @@ QEMU_BUILD_BUG_ON(sizeof(TCGOp) != 8 + sizeof(TCGArg) * MAX_OPC_PARAM);
QEMU_BUILD_BUG_ON(NB_OPS > (1 << 8));
QEMU_BUILD_BUG_ON(OPC_BUF_SIZE > (1 << 16));

typedef struct TCGProfile {
int64_t tb_count1;
int64_t tb_count;
int64_t op_count; /* total insn count */
int op_count_max; /* max insn per TB */
int64_t temp_count;
int temp_count_max;
int64_t del_op_count;
int64_t code_in_len;
int64_t code_out_len;
int64_t search_out_len;
int64_t interm_time;
int64_t code_time;
int64_t la_time;
int64_t opt_time;
int64_t restore_count;
int64_t restore_time;
int64_t table_op_count[NB_OPS];
} TCGProfile;

struct TCGContext {
uint8_t *pool_cur, *pool_end;
TCGPool *pool_first, *pool_current, *pool_first_large;
Expand All @@ -623,23 +643,7 @@ struct TCGContext {
tcg_insn_unit *code_ptr;

#ifdef CONFIG_PROFILER
/* profiling info */
int64_t tb_count1;
int64_t tb_count;
int64_t op_count; /* total insn count */
int op_count_max; /* max insn per TB */
int64_t temp_count;
int temp_count_max;
int64_t del_op_count;
int64_t code_in_len;
int64_t code_out_len;
int64_t search_out_len;
int64_t interm_time;
int64_t code_time;
int64_t la_time;
int64_t opt_time;
int64_t restore_count;
int64_t restore_time;
TCGProfile prof;
#endif

#ifdef CONFIG_DEBUG_TCG
Expand Down

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