fix futex

[lttv.git] / usertrace-fast / ltt / ltt-usertrace-fast.h

diff --git a/usertrace-fast/ltt/ltt-usertrace-fast.h b/usertrace-fast/ltt/ltt-usertrace-fast.h
index a175d895d8d2c21d13828273ceabb6bceaea13c2..77e0594ff58045c5c8fdb817c1656e95e74558d7 100644 (file)
--- a/usertrace-fast/ltt/ltt-usertrace-fast.h
+++ b/usertrace-fast/ltt/ltt-usertrace-fast.h
@@ -33,17 +33,11 @@ static inline __attribute__((no_instrument_function))
 #define LTT_N_SUBBUFS 2
 #endif //LTT_N_SUBBUFS
 
-#ifndef        LTT_SUBBUF_SIZE_CPU
-#define LTT_SUBBUF_SIZE_CPU 1048576
+#ifndef        LTT_SUBBUF_SIZE_PROCESS
+#define LTT_SUBBUF_SIZE_PROCESS 1048576
 #endif //LTT_BUF_SIZE_CPU
 
-#define LTT_BUF_SIZE_CPU (LTT_SUBBUF_SIZE_CPU * LTT_N_SUBBUFS)
-
-#ifndef        LTT_SUBBUF_SIZE_FACILITIES
-#define LTT_SUBBUF_SIZE_FACILITIES 4096
-#endif //LTT_BUF_SIZE_FACILITIES
-
-#define LTT_BUF_SIZE_FACILITIES  (LTT_SUBBUF_SIZE_FACILITIES * LTT_N_SUBBUFS)
+#define LTT_BUF_SIZE_PROCESS (LTT_SUBBUF_SIZE_PROCESS * LTT_N_SUBBUFS)
 
 #ifndef LTT_USERTRACE_ROOT
 #define LTT_USERTRACE_ROOT "/tmp/ltt-usertrace"
@@ -118,7 +112,7 @@ struct ltt_buf {
 
        atomic_t        events_lost;
        atomic_t        corrupted_subbuffers;
-       atomic_t        full;   /* futex on which the writer waits : 1 : full */
+       atomic_t        writer_futex;   /* futex on which the writer waits */
        unsigned int    alloc_size;
        unsigned int    subbuf_size;
 };
@@ -129,10 +123,8 @@ struct ltt_trace_info {
        pid_t daemon_id;
        int nesting;
        struct {
-               struct ltt_buf facilities;
-               struct ltt_buf cpu;
-               char facilities_buf[LTT_BUF_SIZE_FACILITIES] __attribute__ ((aligned (8)));
-               char cpu_buf[LTT_BUF_SIZE_CPU] __attribute__ ((aligned (8)));
+               struct ltt_buf process;
+               char process_buf[LTT_BUF_SIZE_PROCESS] __attribute__ ((aligned (8)));
        } channel;
 };
 
@@ -171,7 +163,7 @@ static inline unsigned int __attribute__((no_instrument_function))
                ltt_get_index_from_facility(ltt_facility_t fID,
                                                                                                                                uint8_t eID)
 {
-       return GET_CHANNEL_INDEX(cpu);
+       return GET_CHANNEL_INDEX(process);
 }
 
 
@@ -423,23 +415,28 @@ static inline void * __attribute__((no_instrument_function)) ltt_reserve_slot(
                                                                                                                                                                                 ltt_buf)]);
                        if(reserve_commit_diff == 0) {
                                /* Next buffer not corrupted. */
-                               if((SUBBUF_TRUNC(offset_begin, ltt_buf) 
-                                                               - SUBBUF_TRUNC(atomic_read(&ltt_buf->consumed), ltt_buf))
-                                                                       >= ltt_buf->alloc_size) {
-                                       /* We block until the reader unblocks us */
-                                       atomic_set(&ltt_buf->full, 1);
-                                       /* We block until the reader tells us to wake up.
-                                                Signals will simply cause this loop to restart.
-                                                */
-                                       do {
-                                               ret = futex((unsigned long)&ltt_buf->full, FUTEX_WAIT, 1, 0, 0, 0);
-                                       } while(ret != 0 && ret != EWOULDBLOCK);
+                               //if((SUBBUF_TRUNC(offset_begin, ltt_buf) 
+                               //                              - SUBBUF_TRUNC(atomic_read(&ltt_buf->consumed), ltt_buf))
+                               //                                      >= ltt_buf->alloc_size) {
+                                       if(atomic_dec_return(&ltt_buf->writer_futex) >= 0) {
+                                               /* non contended */
+                                       } else {
+                                               /* We block until the reader unblocks us */
+                                               atomic_set(&ltt_buf->writer_futex, -1);
+                                               /* We block until the reader tells us to wake up.
+                                                        Signals will simply cause this loop to restart.
+                                                        */
+                                               do {
+                                                       ret = futex((unsigned long)&ltt_buf->writer_futex,
+                                                                       FUTEX_WAIT, -1, 0, 0, 0);
+                                               } while(ret != 0 && ret != EWOULDBLOCK);
+                                       }
                                        /* go on with the write */
 
-                               } else {
-                                       /* next buffer not corrupted, we are either in overwrite mode or
-                                        * the buffer is not full. It's safe to write in this new subbuffer.*/
-                               }
+                               //} else {
+                               //      /* next buffer not corrupted, we are either in overwrite mode or
+                               //       * the buffer is not full. It's safe to write in this new subbuffer.*/
+                               //}
                        } else {
                                /* Next subbuffer corrupted. Force pushing reader even in normal
                                 * mode. It's safe to write in this new subbuffer. */