Convert buffering system to per-cpu

[ust.git] / libust / serialize.c

diff --git a/libust/serialize.c b/libust/serialize.c
index d603815b50621e74332f96301d1b6b9a38266200..9cb6bcaed6cd52794a01ebbc80635c197fb4b6d1 100644 (file)
--- a/libust/serialize.c
+++ b/libust/serialize.c
@@ -24,6 +24,9 @@
  * va_list * to ltt_vtrace.
  */
 
+#define _GNU_SOURCE
+#include <unistd.h>
+#include <sys/syscall.h>
 #include <stdarg.h>
 #include <string.h>
 #include <stdint.h>
@@ -46,6 +49,11 @@ enum ltt_type {
        LTT_TYPE_NONE,
 };
 
+static int ust_get_cpu(void)
+{
+       return sched_getcpu();
+}
+
 #define LTT_ATTRIBUTE_NETWORK_BYTE_ORDER (1<<1)
 
 /*
@@ -684,7 +692,7 @@ notrace void ltt_vtrace(const struct marker *mdata, void *probe_data,
        struct ltt_serialize_closure closure;
        struct ltt_probe_private_data *private_data = call_data;
        void *serialize_private = NULL;
-//ust//        int cpu;
+       int cpu;
        unsigned int rflags;
 
        /*
@@ -696,7 +704,9 @@ notrace void ltt_vtrace(const struct marker *mdata, void *probe_data,
 
        rcu_read_lock(); //ust// rcu_read_lock_sched_notrace();
 //ust//        cpu = smp_processor_id();
+       cpu = ust_get_cpu();
 //ust//        __get_cpu_var(ltt_nesting)++;
+       /* FIXME: should nesting be per-cpu? */
        ltt_nesting++;
 
        pdata = (struct ltt_active_marker *)probe_data;
@@ -750,18 +760,26 @@ notrace void ltt_vtrace(const struct marker *mdata, void *probe_data,
                if (!channel->active)
                        continue;
 
+               /* If a new cpu was plugged since the trace was started, we did
+                * not add it to the trace, and therefore we write the event to
+                * cpu 0.
+                */
+               if(cpu >= channel->n_cpus) {
+                       cpu = 0;
+               }
+
                /* reserve space : header and data */
                ret = ltt_reserve_slot(trace, channel, &transport_data,
                                        data_size, &slot_size, &buf_offset,
                                        &tsc, &rflags,
-                                       largest_align);
+                                       largest_align, cpu);
                if (unlikely(ret < 0))
                        continue; /* buffer full */
 
                va_copy(args_copy, *args);
                /* FIXME : could probably encapsulate transport better. */
 //ust//                buf = ((struct rchan *)channel->trans_channel_data)->buf[cpu];
-               buf = channel->buf;
+               buf = channel->buf[cpu];
                /* Out-of-order write : header and data */
                buf_offset = ltt_write_event_header(trace,
                                        buf, buf_offset,