diff options
| author | Chen Guo <chenguo4@ucla.edu> | 2010-12-06 00:15:42 -0800 |
|---|---|---|
| committer | Paul Eggert <eggert@cs.ucla.edu> | 2010-12-11 00:29:13 -0800 |
| commit | 621876ff446885d32922f34681790581c994f9a5 (patch) | |
| tree | e279f95ce07f9d267e14a8e09f79ae31622e3f02 | |
| parent | 195c455d0ae3884ab2d9680ac3043aa36e9c8c3d (diff) | |
| download | coreutils-621876ff446885d32922f34681790581c994f9a5.tar.xz | |
sort: use mutexes, not spinlocks (avoid busy loop on blocked output)
Running a command like this on a multi-core system
sort < big-file | less
would peg all processors at near 100% utilization.
* src/sort.c: (struct merge_node) Change member lock to mutex.
All uses changed.
* tests/Makefile.am (XFAIL_TESTS): Remove definition, now that
this test passes once again. I.e., the sort-spinlock-abuse test
no longer fails.
* NEWS (Bug reports): Mention this.
Reported by DJ Lucas in http://debbugs.gnu.org/7489.
| -rw-r--r-- | NEWS | 5 | ||||
| -rw-r--r-- | src/sort.c | 14 | ||||
| -rw-r--r-- | tests/Makefile.am | 3 |
3 files changed, 12 insertions, 10 deletions
@@ -13,6 +13,11 @@ GNU coreutils NEWS -*- outline -*- sort -u with at least two threads could attempt to read through a corrupted pointer. [bug introduced in coreutils-8.6] + sort with at least two threads and with blocked output would busy-loop + (spinlock) all threads, often using 100% of available CPU cycles to + do no work. I.e., "sort < big-file | less" could waste a lot of power. + [bug introduced in coreutils-8.6] + ** New features split accepts the --number option to generate a specific number of files. diff --git a/src/sort.c b/src/sort.c index a4c2cbf90..9cfc8144f 100644 --- a/src/sort.c +++ b/src/sort.c @@ -241,7 +241,7 @@ struct merge_node struct merge_node *parent; /* Parent node. */ unsigned int level; /* Level in merge tree. */ bool queued; /* Node is already in heap. */ - pthread_spinlock_t lock; /* Lock for node operations. */ + pthread_mutex_t lock; /* Lock for node operations. */ }; /* Priority queue of merge nodes. */ @@ -3157,7 +3157,7 @@ compare_nodes (void const *a, void const *b) static inline void lock_node (struct merge_node *node) { - pthread_spin_lock (&node->lock); + pthread_mutex_lock (&node->lock); } /* Unlock a merge tree NODE. */ @@ -3165,7 +3165,7 @@ lock_node (struct merge_node *node) static inline void unlock_node (struct merge_node *node) { - pthread_spin_unlock (&node->lock); + pthread_mutex_unlock (&node->lock); } /* Destroy merge QUEUE. */ @@ -3479,7 +3479,7 @@ sortlines (struct line *restrict lines, struct line *restrict dest, node.parent = parent; node.level = parent->level + 1; node.queued = false; - pthread_spin_init (&node.lock, PTHREAD_PROCESS_PRIVATE); + pthread_mutex_init (&node.lock, NULL); /* Calculate thread arguments. */ unsigned long int lo_threads = nthreads / 2; @@ -3515,7 +3515,7 @@ sortlines (struct line *restrict lines, struct line *restrict dest, merge_loop (queue, total_lines, tfp, temp_output); } - pthread_spin_destroy (&node.lock); + pthread_mutex_destroy (&node.lock); } /* Scan through FILES[NTEMPS .. NFILES-1] looking for a file that is @@ -3799,12 +3799,12 @@ sort (char * const *files, size_t nfiles, char const *output_file, node.parent = NULL; node.level = MERGE_END; node.queued = false; - pthread_spin_init (&node.lock, PTHREAD_PROCESS_PRIVATE); + pthread_mutex_init (&node.lock, NULL); sortlines (line, line, nthreads, buf.nlines, &node, true, &queue, tfp, temp_output); queue_destroy (&queue); - pthread_spin_destroy (&node.lock); + pthread_mutex_destroy (&node.lock); } else write_unique (line - 1, tfp, temp_output); diff --git a/tests/Makefile.am b/tests/Makefile.am index d52f67737..b5730617e 100644 --- a/tests/Makefile.am +++ b/tests/Makefile.am @@ -656,7 +656,4 @@ pr_data = \ pr/ttb3-FF \ pr/w72l24f-ll -XFAIL_TESTS = \ - misc/sort-spinlock-abuse - include $(srcdir)/check.mk |