tdb: Raw performance torture to beat tdb_increment_seqnum

Running this on sn-devel-184 takes ~14 seconds with the atomic
ops. Without them I did not wait for it to finish. After reducing
NPROCS from 500 to 50 it still ran for more than a minute.

Signed-off-by: Volker Lendecke <vl@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>

Autobuild-User(master): Jeremy Allison <jra@samba.org>
Autobuild-Date(master): Wed Dec 15 01:03:56 UTC 2021 on sn-devel-184

lib/tdb/tools/tdbtortseq.c

@@ -0,0 +1,123 @@
+/*
+ * Unix SMB/CIFS implementation.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "replace.h"
+#include "system/filesys.h"
+#include <tdb.h>
+#include <stdio.h>
+#include <errno.h>
+#include "system/wait.h"
+
+#define NPROCS 500
+#define NUMOPS 1000000
+
+int main(void)
+{
+	pid_t pids[NPROCS];
+	struct tdb_context *tdb = NULL;
+	int i;
+	uint32_t seqnum_before, seqnum_after;
+
+	tdb = tdb_open("seqnum_test.tdb",
+		       10000,
+		       TDB_CLEAR_IF_FIRST|
+		       TDB_SEQNUM|
+		       TDB_INCOMPATIBLE_HASH|
+		       TDB_MUTEX_LOCKING,
+		       O_CREAT|O_RDWR,
+		       0644);
+	if (tdb == NULL) {
+		perror("tdb_open failed");
+		return 1;
+	}
+	seqnum_before = tdb_get_seqnum(tdb);
+
+	for (i=0; i<NPROCS; i++) {
+		pids[i] = fork();
+		if (pids[i] == -1) {
+			perror("fork failed");
+			return 1;
+		}
+		if (pids[i] == 0) {
+			pid_t mypid = getpid();
+			int ret;
+			int j;
+
+			ret = tdb_reopen(tdb);
+			if (ret != 0) {
+				perror("tdb_reopen failed");
+				return 1;
+			}
+
+			for (j=0; j<NUMOPS; j++) {
+				TDB_DATA key = {
+					.dptr = (uint8_t *)&mypid,
+					.dsize = sizeof(mypid),
+				};
+				TDB_DATA value = {
+					.dptr = (uint8_t *)&j,
+					.dsize = sizeof(j),
+				};
+				ret = tdb_store(tdb, key, value, 0);
+				if (ret == -1) {
+					perror("tdb_store failed");
+					return 1;
+				}
+			}
+
+			return 0;
+		}
+	}
+
+	for (i=0; i<NPROCS; i++) {
+		int wstatus;
+		pid_t ret = waitpid(pids[i], &wstatus, 0);
+
+		if (ret == -1) {
+			perror("waitpid failed");
+			return 1;
+		}
+
+		if (!WIFEXITED(wstatus)) {
+			fprintf(stderr,
+				"pid %d did not exit properly\n",
+				(int)pids[i]);
+			return 1;
+		}
+
+		if (WEXITSTATUS(wstatus) != 0) {
+			fprintf(stderr,
+				"pid %d returned %d\n",
+				(int)pids[i],
+				WEXITSTATUS(wstatus));
+			return 1;
+		}
+	}
+
+	seqnum_after = tdb_get_seqnum(tdb);
+
+	printf("seqnum_before=%"PRIu32", seqnum_after=%"PRIu32"\n",
+	       seqnum_before,
+	       seqnum_after);
+
+	if ((seqnum_after - seqnum_before) != (NPROCS*NUMOPS)) {
+		perror("incrementing seqnum failed");
+		return 1;
+	}
+
+	return 0;
+}

lib/tdb/wscript

@@ -145,6 +145,11 @@ def build(bld):
                          'tdb',
                          install=False)
 
+        bld.SAMBA_BINARY('tdbtortseq',
+                         'tools/tdbtortseq.c',
+                         'tdb',
+                         install=False)
+
         bld.SAMBA_BINARY('tdbrestore',
                          'tools/tdbrestore.c',
                          'tdb', manpages='man/tdbrestore.8')