diff options
Diffstat (limited to 'mutrace.c')
| -rw-r--r-- | mutrace.c | 155 |
1 files changed, 127 insertions, 28 deletions
@@ -38,6 +38,7 @@ #include <sched.h> #include <malloc.h> #include <signal.h> +#include <math.h> #if !defined (__linux__) || !defined(__GLIBC__) #error "This stuff only works on Linux!" @@ -146,6 +147,44 @@ static volatile bool threads_existing = false; static uint64_t nsec_timestamp_setup; +/* Must be kept in sync with summary_order_details. */ +typedef enum { + ORDER_ID = 0, + ORDER_N_LOCKED, + ORDER_N_OWNER_CHANGED, + ORDER_N_CONTENDED, + ORDER_NSEC_LOCKED_TOTAL, + ORDER_NSEC_LOCKED_MAX, + ORDER_NSEC_LOCKED_AVG, + ORDER_NSEC_CONTENDED_TOTAL, + ORDER_NSEC_CONTENDED_AVG, + ORDER_NSEC_READ_CONTENDED_TOTAL, +} SummaryOrder; +#define ORDER_INVALID ORDER_NSEC_READ_CONTENDED_TOTAL + 1 /* first invalid order */ + +typedef struct { + const char *command; /* as passed to --order command line argument */ + const char *ui_string; /* as displayed by show_summary() */ +} SummaryOrderDetails; + +/* Must be kept in sync with SummaryOrder. */ +static const SummaryOrderDetails summary_order_details[] = { + { "id", "mutex number" }, + { "n-locked", "lock count" }, + { "n-owner-changed", "owner change count" }, + { "n-contended", "contention count" }, + { "nsec-locked-total", "total time locked" }, + { "nsec-locked-max", "maximum time locked" }, + { "nsec-locked-avg", "average time locked" }, + { "nsec-contended-total", "total time contended" }, + { "nsec-contended-avg", "average time contended" }, + { "nsec-read-contended-total", "total time (read) contended" }, +}; + +static SummaryOrder summary_order = ORDER_N_CONTENDED; + +static SummaryOrder summary_order_from_command(const char *command); + static void setup(void) __attribute ((constructor)); static void shutdown(void) __attribute ((destructor)); @@ -202,6 +241,17 @@ static int parse_env(const char *n, unsigned *t) { return 0; } +/* Maximum tolerated relative error when comparing doubles */ +#define MAX_RELATIVE_ERROR 0.001 + +static bool doubles_equal(double a, double b) { + /* Make sure we don't divide by zero. */ + if (fpclassify(b) == FP_ZERO) + return (fpclassify(a) == FP_ZERO); + + return ((a - b) / b <= MAX_RELATIVE_ERROR); +} + #define LOAD_FUNC(name) \ do { \ *(void**) (&real_##name) = dlsym(RTLD_NEXT, #name); \ @@ -269,6 +319,7 @@ static void setup(void) { pthread_mutex_t *m, *last; int r; unsigned t; + const char *s; load_functions(); @@ -339,6 +390,15 @@ static void setup(void) { else show_n_max = t; + s = getenv("MUTRACE_SUMMARY_ORDER"); + if (s != NULL) { + t = summary_order_from_command(s); + if (t == ORDER_INVALID) + fprintf(stderr, "mutrace: WARNING: Failed to parse $MUTRACE_SUMMARY_ORDER.\n"); + else + summary_order = t; + } + if (getenv("MUTRACE_TRAP")) raise_trap = true; @@ -417,33 +477,60 @@ static int mutex_info_compare(const void *_a, const void *_b) { *a = *(const struct mutex_info**) _a, *b = *(const struct mutex_info**) _b; - if (a->n_contended > b->n_contended) - return -1; - else if (a->n_contended < b->n_contended) - return 1; + /* Order by the user's chosen ordering first, then fall back to a static + * ordering. */ + switch (summary_order) { + #define ORDER_CASE(UCASE, lcase) \ + case ORDER_##UCASE: \ + if (a->lcase != b->lcase) \ + return a->lcase - b->lcase; \ + break; - if (a->n_owner_changed > b->n_owner_changed) - return -1; - else if (a->n_owner_changed < b->n_owner_changed) - return 1; + ORDER_CASE(ID, id) + ORDER_CASE(N_LOCKED, n_locked) + ORDER_CASE(N_OWNER_CHANGED, n_owner_changed) + ORDER_CASE(N_CONTENDED, n_contended) + ORDER_CASE(NSEC_LOCKED_TOTAL, nsec_locked_total) + ORDER_CASE(NSEC_LOCKED_MAX, nsec_locked_max) + ORDER_CASE(NSEC_CONTENDED_TOTAL, nsec_contended_total) + ORDER_CASE(NSEC_READ_CONTENDED_TOTAL, nsec_read_contended_total) + case ORDER_NSEC_LOCKED_AVG: { + double a_avg = a->nsec_locked_total / a->n_locked, + b_avg = b->nsec_locked_total / b->n_locked; + + if (!doubles_equal(a_avg, b_avg)) + return ((a_avg - b_avg) < 0.0) ? -1 : 1; + break; + } + case ORDER_NSEC_CONTENDED_AVG: { + double a_avg = a->nsec_contended_total / a->n_contended, + b_avg = b->nsec_contended_total / b->n_contended; - if (a->n_locked > b->n_locked) - return -1; - else if (a->n_locked < b->n_locked) - return 1; + if (!doubles_equal(a_avg, b_avg)) + return ((a_avg - b_avg) < 0.0) ? -1 : 1; + break; + } + default: + /* Should never be reached. */ + assert(0); - if (a->nsec_locked_max > b->nsec_locked_max) - return -1; - else if (a->nsec_locked_max < b->nsec_locked_max) - return 1; + #undef ORDER_CASE + } - /* Let's make the output deterministic */ - if (a > b) - return -1; - else if (a < b) - return 1; + /* Fall back to a static ordering. */ + #define STATIC_ORDER(lcase) \ + if (a->lcase != b->lcase) \ + return a->lcase - b->lcase - return 0; + STATIC_ORDER(n_contended); + STATIC_ORDER(n_owner_changed); + STATIC_ORDER(n_locked); + STATIC_ORDER(nsec_locked_max); + + #undef STATIC_ORDER + + /* Let's make the output deterministic */ + return a - b; } static bool mutex_info_show(struct mutex_info *mi) { @@ -559,6 +646,18 @@ static bool mutex_info_stat(struct mutex_info *mi) { return true; } +static SummaryOrder summary_order_from_command(const char *command) { + unsigned int i; + + for (i = 0; i < ORDER_INVALID; i++) { + if (strcmp(command, summary_order_details[i].command) == 0) { + return ORDER_ID; + } + } + + return ORDER_INVALID; +} + static void show_summary_internal(void) { struct mutex_info *mi, **table; unsigned n, u, i, m; @@ -609,19 +708,19 @@ static void show_summary_internal(void) { qsort(table, n, sizeof(table[0]), mutex_info_compare); - for (i = 0, m = 0; i < n && (show_n_max <= 0 || m < show_n_max); i++) - m += mutex_info_dump(table[i]) ? 1 : 0; + for (i = n, m = 0; i > 0 && (show_n_max <= 0 || m < show_n_max); i--) + m += mutex_info_dump(table[i - 1]) ? 1 : 0; if (m > 0) { fprintf(stderr, "\n" - "mutrace: Showing %u most contended mutexes:\n" + "mutrace: Showing %u mutexes in order of %s:\n" "\n" " Mutex # Locked Changed Cont. cont.Time[ms] tot.Time[ms] avg.Time[ms] Flags\n", - m); + m, summary_order_details[summary_order].ui_string); - for (i = 0, m = 0; i < n && (show_n_max <= 0 || m < show_n_max); i++) - m += mutex_info_stat(table[i]) ? 1 : 0; + for (i = n, m = 0; i > 0 && (show_n_max <= 0 || m < show_n_max); i--) + m += mutex_info_stat(table[i - 1]) ? 1 : 0; if (i < n) |