use asm/cpuid instead of /proc/cpuinfo to detect hyperthreading
This commit is contained in:
Doug MacEachern
parent
2debe9948e
commit
249653c046
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@ -127,7 +127,11 @@ int sigar_os_open(sigar_t **sigar)
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(*sigar)->last_proc_stat.pid = -1;
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#ifdef __LP64__
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(*sigar)->ht_enabled = 0;
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#else
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(*sigar)->ht_enabled = -1;
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#endif
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if (stat(PROC_DISKSTATS, &sb) == 0) {
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(*sigar)->iostat = IOSTAT_DISKSTATS;
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@ -162,17 +166,74 @@ char *sigar_os_error_string(sigar_t *sigar, int err)
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return NULL;
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}
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#define INTEL_ID 0x756e6547
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static void sigar_cpuid(unsigned long request,
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unsigned long *eax,
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unsigned long *ebx,
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unsigned long *ecx,
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unsigned long *edx)
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{
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#if 0
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/* does not compile w/ -fPIC */
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/* can't find a register in class `BREG' while reloading `asm' */
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asm volatile ("cpuid" :
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"=a" (*eax),
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"=b" (*ebx),
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"=c" (*ecx),
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"=d" (*edx)
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: "a" (request));
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#else
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/* derived from: */
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/* http://svn.red-bean.com/repos/minor/trunk/gc/barriers-ia-32.c */
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asm volatile ("mov %%ebx, %%esi\n\t"
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"cpuid\n\t"
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"xchgl %%ebx, %%esi"
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: "=a" (*eax),
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"=S" (*ebx),
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"=c" (*ecx),
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"=d" (*edx)
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: "0" (request)
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: "memory");
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#endif
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}
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static int is_ht_enabled(sigar_t *sigar)
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{
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if (sigar->ht_enabled == -1) {
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unsigned long eax, ebx, ecx, edx;
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if (sigar->ht_enabled != -1) {
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/* only check once */
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sigar_cpu_info_list_t cpuinfos;
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return sigar->ht_enabled;
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}
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if (sigar_cpu_info_list_get(sigar, &cpuinfos) != SIGAR_OK) {
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sigar->ht_enabled = 0; /* chances we reach here: slim..none */
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sigar->ht_enabled = 0;
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sigar->lcpu = 0;
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sigar_cpuid(0, &eax, &ebx, &ecx, &edx);
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if (ebx == INTEL_ID) {
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sigar_cpuid(1, &eax, &ebx, &ecx, &edx);
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if (edx & (1<<28)) {
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sigar->lcpu = (ebx & 0x00FF0000) >> 16;
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if (sigar->lcpu > 1) {
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sigar->ht_enabled = 1;
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sigar_log_printf(sigar, SIGAR_LOG_DEBUG,
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"[cpu] HT enabled, siblings: %d",
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sigar->lcpu);
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}
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else {
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sigar_log(sigar, SIGAR_LOG_DEBUG,
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"[cpu] HT supported, not enabled.");
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}
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}
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sigar_cpu_info_list_destroy(sigar, &cpuinfos);
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}
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else {
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sigar_log(sigar, SIGAR_LOG_DEBUG,
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"[cpu] HT not supported.");
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sigar->lcpu = 1;
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}
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return sigar->ht_enabled;
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@ -1347,13 +1408,11 @@ static SIGAR_INLINE void cpu_info_strcpy(char *ptr, char *buf, int len)
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}
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static int get_cpu_info(sigar_t *sigar, sigar_cpu_info_t *info,
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FILE *fp, int *id)
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FILE *fp)
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{
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char buffer[BUFSIZ], *ptr;
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int found = 0, siblings = 0;
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*id = -1;
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int found = 0;
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while ((ptr = fgets(buffer, sizeof(buffer), fp))) {
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switch (*ptr) {
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@ -1361,10 +1420,6 @@ static int get_cpu_info(sigar_t *sigar, sigar_cpu_info_t *info,
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if (strnEQ(ptr, "processor", 9)) {
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found = 1;
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}
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else if (strnEQ(ptr, "physical id", 11)) {
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ptr = cpu_info_strval(ptr);
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*id = atoi(ptr);
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}
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break;
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case 'v':
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if (strnEQ(ptr, "vendor_id", 9)) {
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@ -1393,30 +1448,6 @@ static int get_cpu_info(sigar_t *sigar, sigar_cpu_info_t *info,
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info->cache_size = sigar_strtoul(ptr);
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}
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break;
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case 's':
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/* this is horseshit. why doesn't linux have a real api
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* like every other operation system. if siblings == 1
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* then hyperthreading is disabled, so we shouldn't fold
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* the dups based on physical id attribute.
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*/
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if (strnEQ(ptr, "siblings", 8)) {
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ptr = cpu_info_strval(ptr);
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siblings = atoi(ptr);
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if (siblings == 1) {
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*id = -1;
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}
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}
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break;
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case 't':
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/* same as siblings, renamed in new kernels */
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if (strnEQ(ptr, "threads", 7)) {
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ptr = cpu_info_strval(ptr);
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siblings = atoi(ptr);
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if (siblings == 1) {
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*id = -1;
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}
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}
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break;
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/* lone \n means end of info for this processor */
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case '\n':
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return found;
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@ -1430,55 +1461,17 @@ int sigar_cpu_info_list_get(sigar_t *sigar,
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sigar_cpu_info_list_t *cpu_infos)
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{
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FILE *fp;
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int id, fake_id = -1;
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int cpu_id[36], cpu_ix=0;
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/* in the event that a box has > 36 cpus */
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int cpu_id_max = sizeof(cpu_id)/sizeof(int);
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int hthread = is_ht_enabled(sigar), i=0;
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if (!(fp = fopen(PROC_FS_ROOT "cpuinfo", "r"))) {
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return errno;
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}
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sigar->ht_enabled = 0; /* figure out below */
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sigar_cpu_info_list_create(cpu_infos);
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memset(&cpu_id[0], -1, sizeof(cpu_id));
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while (get_cpu_info(sigar, &cpu_infos->data[cpu_infos->number], fp, &id)) {
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fake_id++;
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if (id >= 0) {
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int i, fold=0;
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for (i=0; (i<cpu_ix) && (i<cpu_id_max); i++) {
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if (cpu_id[i] == id) {
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fold = 1;
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break;
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}
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}
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/* e.g. each Intel Xeon cpu is reported twice */
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/* fold dups based on physical id */
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if (fold) {
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sigar->ht_enabled = 1;
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sigar->lcpu = 2; /* XXX assume 2 for now */
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continue;
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}
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else {
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if (cpu_ix < cpu_id_max) {
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cpu_id[cpu_ix++] = id;
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}
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}
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}
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else if (strEQ(cpu_infos->data[cpu_infos->number].model, "Xeon")) {
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/* Redhat AS 2.1 /proc/cpuinfo does not have any of the
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* attributes we use to detect hyperthreading, in this case
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* if model Xeon, assume HT enabled. FUCK IT.
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*/
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if (fake_id % 2) {
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sigar->ht_enabled = 1;
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sigar->lcpu = 2; /* XXX assume 2 for now */
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continue;
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}
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while (get_cpu_info(sigar, &cpu_infos->data[cpu_infos->number], fp)) {
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if (hthread && (i++ % sigar->lcpu)) {
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continue; /* fold logical processors if HT */
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}
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++cpu_infos->number;
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