Author: Armin Rigo <ar...@tunes.org>
Branch: c6
Changeset: r590:262fa1563851
Date: 2013-12-29 10:44 +0100
http://bitbucket.org/pypy/stmgc/changeset/262fa1563851/

Log:    Adapt update_to_leader() to release the lock when copying the
        objects

diff --git a/checkfence/c6/test4.c b/checkfence/c6/test4.c
new file mode 100644
--- /dev/null
+++ b/checkfence/c6/test4.c
@@ -0,0 +1,266 @@
+#include "lsl_protos.h"
+
+typedef unsigned short uint16_t;
+typedef boolean_t bool;
+
+
+#define NUM_THREADS  2
+#define UNDOLOG      NUM_THREADS
+
+
+typedef unsigned uid_t;
+
+
+typedef struct {
+    uid_t    read_version;
+    char     flag_modified;
+    int      value1, value2;
+} object_t;
+
+typedef struct {
+    int n_modified_objects;
+    uid_t transaction_read_version;
+} thread_local_t;
+
+thread_local_t tl[NUM_THREADS];
+object_t obj[NUM_THREADS+1];
+int n_global_history;
+int leader_thread_num;
+lsl_lock_t undo_lock;
+
+
+void setup(void)
+{
+    /* initialize global state */
+    leader_thread_num = 0;
+    n_global_history = 0;
+    lsl_initlock(&undo_lock);
+
+    /* XXX manual unrolling */
+    tl[0].n_modified_objects = 0;
+    tl[0].transaction_read_version = 0;
+    tl[1].n_modified_objects = 0;
+    tl[1].transaction_read_version = 0;
+}
+
+
+int fetch_and_add(volatile int *loc, int increment)
+{
+    int oldvalue = *loc;
+    lsl_assume(lsl_cas_64(loc, oldvalue, oldvalue + increment));
+    return oldvalue;
+}
+
+/* int stm_allocate(int t) */
+/* { */
+/*     int result = fetch_and_add(&next_free_glob, 1); */
+/*     lsl_observe_output("stm_allocate", result); */
+
+/*     obj[t][result].flag_modified = true; */
+/*     return result; */
+/* } */
+
+int acquire_lock_if_leader(int t)
+{
+    //XXX:
+    //if (leader_thread_num != t)
+    //    return 0;
+    lsl_lock(&undo_lock);
+    if (leader_thread_num == t)
+        return 1;
+    lsl_unlock(&undo_lock);
+    return 0;
+}
+
+void memcpy_obj_without_header(int tdst, int tsrc)
+{
+    obj[tdst].value1        = obj[tsrc].value1;
+    obj[tdst].value2        = obj[tsrc].value2;
+}
+
+#define stm_read(t)  \
+    (obj[t].read_version = tl[t].transaction_read_version)
+
+void stm_write(int t)
+{
+    if (obj[t].flag_modified)
+        return;   /* already modified during this transaction */
+
+    stm_read(t);
+
+    int is_leader = acquire_lock_if_leader(t);
+    obj[t].flag_modified = true;
+    tl[t].n_modified_objects = 1;
+    if (is_leader) {
+        memcpy_obj_without_header(UNDOLOG, t);
+        lsl_unlock(&undo_lock);
+    }
+}
+
+int update_to_leader(int t, int check)
+{
+    /* becomes the leader, and update the local copy of the objects */
+    uid_t my_version = tl[t].transaction_read_version;
+    int result = check;
+
+    if (n_global_history > 0) {
+        int nmod = tl[1 - t].n_modified_objects;
+        lsl_unlock(&undo_lock);
+
+        /* loop over objects in 'global_history': if they have been
+           read by the current transaction, the current transaction must
+           abort; then copy them out of the leader's object space ---
+           which may have been modified by the leader's uncommitted
+           transaction; this case will be fixed afterwards. */
+        if (result)
+            result = (obj[t].read_version != my_version);
+        memcpy_obj_without_header(t, 1 - t);
+
+        /* finally, loop over objects modified by the leader,
+           and copy them out of the undo log.  XXX We could use
+           a heuristic to avoid copying unneeded objects: it's not
+           useful to copy objects that were not also present in
+           the 'global_history'. */
+        if (!nmod) {
+            lsl_lock(&undo_lock);
+            nmod = tl[1 - t].n_modified_objects;
+            if (nmod)
+                lsl_unlock(&undo_lock);
+        }
+        if (nmod) {
+            memcpy_obj_without_header(t, UNDOLOG);
+            lsl_lock(&undo_lock);
+        }
+
+        n_global_history = 0;
+    }
+    leader_thread_num = t;
+    return result;
+}
+
+void update_state(int t)
+{
+    lsl_lock(&undo_lock);
+    if (leader_thread_num != t) {
+        update_to_leader(t, 0);
+    }
+    lsl_unlock(&undo_lock);
+}
+
+void start_transaction(int t)
+{
+    lsl_assert(tl[t].n_modified_objects == 0);
+    lsl_assert(!obj[t].flag_modified);
+    tl[t].transaction_read_version++;
+}
+
+int stop_transaction(int t)
+{
+    int nmod = tl[t].n_modified_objects;
+    if (nmod == 0) {
+        /* no modified objects in this transaction */
+        return 1;
+    }
+
+    lsl_lock(&undo_lock);
+
+    int result;
+    if (leader_thread_num == t) {
+        result = 1;
+    }
+    else {
+        result = update_to_leader(t, 1);
+    }
+
+    if (result) {
+        obj[t].flag_modified = false;
+        n_global_history = 1;
+    }
+    else {
+        obj[t].flag_modified = false;
+    }
+    tl[t].n_modified_objects = 0;
+
+    lsl_unlock(&undo_lock);
+    return result;
+}
+
+
+/* void A(void) */
+/* { */
+/*     int t = lsl_get_thread_id(); */
+/*     int num = stm_allocate(t); */
+/* } */
+
+void SETUP(void)
+{
+    setup();
+}
+
+void SETUP100(void)
+{
+    int t = 0;
+    setup();
+
+    /* XXX manual unrolling */
+    obj[0].flag_modified = false;
+    obj[0].read_version = 0;
+    obj[0].value1 = 100;
+    obj[0].value2 = 200;
+
+    obj[1].flag_modified = false;
+    obj[1].read_version = 0;
+    obj[1].value1 = 100;
+    obj[1].value2 = 200;
+}
+
+void R0(void)
+{
+    int t = lsl_get_thread_id();
+    int result1, result2;
+    while (1) {
+        start_transaction(t);
+        stm_read(t);
+        result1 = obj[t].value1;
+        result2 = obj[t].value2;
+        if (stop_transaction(t))
+            break;
+    }
+
+    lsl_observe_output("R0:value1", result1);
+    lsl_observe_output("R0:value2", result2);
+}
+
+void W0INC1(void)
+{
+    int t = lsl_get_thread_id();
+    int nvalue1, nvalue2;
+    //update_state(t);
+
+    start_transaction(t);
+    stm_write(t);
+    nvalue1 = ++obj[t].value1;
+    nvalue2 = ++obj[t].value2;
+    lsl_assert(nvalue1 == obj[t].value1);
+    lsl_assert(nvalue2 == obj[t].value2);
+    if (!stop_transaction(t)) {
+        start_transaction(t);
+        stm_write(t);
+        nvalue1 = ++obj[t].value1;
+        nvalue2 = ++obj[t].value2;
+        lsl_assert(nvalue1 == obj[t].value1);
+        lsl_assert(nvalue2 == obj[t].value2);
+        if (!stop_transaction(t)) {
+            lsl_observe_output("XXX W0INC1 failed twice", 0);
+        }
+    }
+
+    lsl_observe_output("W0INC1:nvalue1", nvalue1);
+    lsl_observe_output("W0INC1:nvalue2", nvalue2);
+}
+
+void UPD(void)
+{
+    int t = lsl_get_thread_id();
+    update_state(t);
+}
diff --git a/checkfence/c6/test4.lsl b/checkfence/c6/test4.lsl
new file mode 100644
--- /dev/null
+++ b/checkfence/c6/test4.lsl
@@ -0,0 +1,6 @@
+
+test T1 = SETUP100 ( R0 | R0 )
+
+test T2 = SETUP100 ( W0INC1 | W0INC1 )
+
+test T3 = SETUP100 ( UPD R0 UPD R0 | W0INC1 )
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