patch3:
After the previous change to flat nesting by default, checkpoints, and
thus having only a single gtm_transaction object per thread, we can move
the local_tid field to gtm_transaction too. As a result, we don't have
to access gtm_thread in GTM_begin_transaction anymore.
patch4:
A small fix that adds a missing set-up call for gtm_thread. And a
matching test case, which tests that the functions in query.cc work even
if no transaction has been executed so far in this thread.
OK for branch?
commit 33c3c869c7cb986bcca3f3f44b0412278e880a82
Author: Torvald Riegel <trie...@redhat.com>
Date: Fri Jul 29 16:09:05 2011 +0200
Move local_tid from gtm_thread to gtm_transaction.
* config/generic/tls.h (gtm_thread): Move local_tid from here ...
* libitm_i.h (local_tid): ... to here.
* beginend.cc (GTM::gtm_transaction::begin_transaction): Same.
(GTM::gtm_transaction::operator new): Set up gtm_thread if necessary.
diff --git a/libitm/beginend.cc b/libitm/beginend.cc
index d336d60..a16c3f9 100644
--- a/libitm/beginend.cc
+++ b/libitm/beginend.cc
@@ -43,7 +43,7 @@ static _ITM_transactionId_t global_tid;
void *
GTM::gtm_transaction::operator new (size_t s)
{
- gtm_thread *thr = gtm_thr ();
+ gtm_thread *thr = setup_gtm_thr ();
void *tx;
assert(s == sizeof(gtm_transaction));
@@ -112,8 +112,6 @@ GTM::gtm_transaction::begin_transaction (uint32_t prop,
const gtm_jmpbuf *jb)
if (unlikely(prop & pr_undoLogCode))
GTM_fatal("pr_undoLogCode not supported");
- gtm_thread *thr = setup_gtm_thr ();
-
tx = gtm_tx();
if (tx == NULL)
{
@@ -214,18 +212,18 @@ GTM::gtm_transaction::begin_transaction (uint32_t prop,
const gtm_jmpbuf *jb)
// As long as we have not exhausted a previously allocated block of TIDs,
// we can avoid an atomic operation on a shared cacheline.
- if (thr->local_tid & (tid_block_size - 1))
- tx->id = thr->local_tid++;
+ if (tx->local_tid & (tid_block_size - 1))
+ tx->id = tx->local_tid++;
else
{
#ifdef HAVE_64BIT_SYNC_BUILTINS
tx->id = __sync_add_and_fetch (&global_tid, tid_block_size);
- thr->local_tid = tx->id + 1;
+ tx->local_tid = tx->id + 1;
#else
pthread_mutex_lock (&global_tid_lock);
global_tid += tid_block_size;
tx->id = global_tid;
- thr->local_tid = tx->id + 1;
+ tx->local_tid = tx->id + 1;
pthread_mutex_unlock (&global_tid_lock);
#endif
}
diff --git a/libitm/config/generic/tls.h b/libitm/config/generic/tls.h
index 82d7c66..8a39b80 100644
--- a/libitm/config/generic/tls.h
+++ b/libitm/config/generic/tls.h
@@ -50,12 +50,6 @@ struct gtm_thread
void *free_tx[MAX_FREE_TX];
unsigned free_tx_idx, free_tx_count;
- // In order to reduce cacheline contention on global_tid during
- // beginTransaction, we allocate a block of 2**N ids to the thread
- // all at once. This number is the next value to be allocated from
- // the block, or 0 % 2**N if no such block is allocated.
- _ITM_transactionId_t local_tid;
-
// The value returned by _ITM_getThreadnum to identify this thread.
// ??? At present, this is densely allocated beginning with 1 and
// we don't bother filling in this value until it is requested.
diff --git a/libitm/libitm_i.h b/libitm/libitm_i.h
index 97f535a..7d475be 100644
--- a/libitm/libitm_i.h
+++ b/libitm/libitm_i.h
@@ -168,6 +168,12 @@ struct gtm_transaction
// A bitmask of the above.
uint32_t state;
+ // In order to reduce cacheline contention on global_tid during
+ // beginTransaction, we allocate a block of 2**N ids to the thread
+ // all at once. This number is the next value to be allocated from
+ // the block, or 0 % 2**N if no such block is allocated.
+ _ITM_transactionId_t local_tid;
+
// Data used by eh_cpp.c for managing exceptions within the transaction.
uint32_t cxa_catch_count;
void *cxa_unthrown;
commit 22c19978ba11c0ae0321449d8809260ab5f97741
Author: Torvald Riegel <trie...@redhat.com>
Date: Fri Jul 29 16:19:41 2011 +0200
Fix missing setup of gtm_thread if no transaction has run yet.
* query.cc (_ITM_getThreadnum): Set up gtm_thread if necessary.
* testsuite/libitm.c/notx.c: New file.
diff --git a/libitm/query.cc b/libitm/query.cc
index 9a95211..02f1813 100644
--- a/libitm/query.cc
+++ b/libitm/query.cc
@@ -67,7 +67,7 @@ int ITM_REGPARM
_ITM_getThreadnum (void)
{
static int global_num;
- struct gtm_thread *thr = gtm_thr();
+ struct gtm_thread *thr = setup_gtm_thr();
int num = thr->thread_num;
if (num == 0)
diff --git a/libitm/testsuite/libitm.c/notx.c b/libitm/testsuite/libitm.c/notx.c
new file mode 100644
index 0000000..92ae3e1
--- /dev/null
+++ b/libitm/testsuite/libitm.c/notx.c
@@ -0,0 +1,36 @@
+/* These tests all check whether initialization happens properly even if no
+ transaction has been used in the current thread yet. */
+#include <stdlib.h>
+#include <pthread.h>
+#include <libitm.h>
+
+static void *test1 (void *dummy __attribute__((unused)))
+{
+ if (_ITM_inTransaction() != outsideTransaction)
+ abort();
+ return NULL;
+}
+
+static void *test2 (void *dummy __attribute__((unused)))
+{
+ if (_ITM_getTransactionId() != _ITM_noTransactionId)
+ abort();
+ return NULL;
+}
+
+
+int main()
+{
+ pthread_t thread;
+
+ if (_ITM_getThreadnum() != 1)
+ abort();
+
+ pthread_create(&thread, NULL, test1, NULL);
+ pthread_join(thread, NULL);
+
+ pthread_create(&thread, NULL, test2, NULL);
+ pthread_join(thread, NULL);
+
+ return 0;
+}
