OK, last one in the series: user level test programs that stress
the kernel I/O stack. Pretty dull stuff.
- Ken
diff -Nur zero/aio_null.c blknull_test/aio_null.c
--- zero/aio_null.c 1969-12-31 16:00:00.000000000 -0800
+++ blknull_test/aio_null.c 2005-03-08 00:46:17.000000000 -0800
@@ -0,0 +1,76 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sched.h>
+#include <signal.h>
+#include <sys/types.h>
+#include <linux/ioctl.h>
+#include <libaio.h>
+
+#define MAXAIO 1024
+
+char buf[4096] __attribute__((aligned(4096)));
+
+io_context_t io_ctx;
+struct iocb iocbpool[MAXAIO];
+struct io_event ioevent[MAXAIO];
+
+void aio_setup(int n)
+{
+ int res = io_queue_init(n, &io_ctx);
+ if (res != 0) {
+ printf("io_queue_setup(%d) returned %d (%s)\n",
+ n, res, strerror(-res));
+ exit(0);
+ }
+}
+
+main(int argc, char* argv[])
+{
+ int fd, i, status, batch;
+ struct iocb* iocbbatch[MAXAIO];
+ int devidx;
+ off_t offset;
+ unsigned long start, end;
+
+ batch = argc < 2 ? 100: atoi(argv[1]);
+ if (batch >= MAXAIO)
+ batch = MAXAIO;
+
+ aio_setup(MAXAIO);
+ fd = open("/dev/raw/raw1", O_RDONLY);
+
+ if (fd == -1) {
+ perror("error opening\n");
+ exit (0);
+ }
+ for (i=0; i<batch; i++) {
+ iocbbatch[i] = iocbpool+i;
+ io_prep_pread(iocbbatch[i], fd, buf, 4096, 0);
+ }
+
+ while (1) {
+ struct timespec ts={30,0};
+ int bufidx;
+ int reap;
+
+ status = io_submit(io_ctx, i, iocbbatch);
+ if (status != i) {
+ printf("bad io_submit: %d [%s]\n", status,
+ strerror(-status));
+ }
+
+ // reap at least batch count back
+ reap = io_getevents(io_ctx, batch, MAXAIO, ioevent, &ts);
+ if (reap < batch) {
+ printf("io_getevents returned=%d [%s]\n", reap,
+ strerror(-reap));
+ }
+
+ // check the return result of each event
+ for (i=0; i<reap; i++)
+ if (ioevent[i].res != 4096)
+ printf("error in read: %lx\n", ioevent[i].res);
+ } /* while (1) */
+}
diff -Nur zero/pread_null.c blknull_test/pread_null.c
--- zero/pread_null.c 1969-12-31 16:00:00.000000000 -0800
+++ blknull_test/pread_null.c 2005-03-08 00:44:20.000000000 -0800
@@ -0,0 +1,27 @@
+#include <stdio.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <malloc.h>
+
+main(int argc, char* argv[])
+{
+ int fd;
+ char *addr;
+
+ fd = open("/dev/raw/raw1", O_RDONLY);
+ if (fd == -1) {
+ perror("error opening\n");
+ exit(0);
+ }
+
+ addr = memalign(4096, 4096);
+ if (addr == 0) {
+ printf("no memory\n");
+ exit(0);
+ }
+
+ while (1) {
+ pread(fd, addr, 4096, 0);
+ }
+
+}
diff -Nur zero/makefile blknull_test/makefile
--- zero/makefile 1969-12-31 16:00:00.000000000 -0800
+++ blknull_test/makefile 2005-03-08 17:10:39.000000000 -0800
@@ -0,0 +1,10 @@
+all: pread_null aio_null
+
+pread_null: pread_null.c
+ gcc -O3 -o $@ pread_null.c
+
+aio_null: aio_null.c
+ gcc -O3 -o $@ aio_null.c -laio
+
+clean:
+ rm -f pread_null aio_null
-
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