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Diffstat (limited to 'blktrace.c')
-rw-r--r--blktrace.c121
1 files changed, 91 insertions, 30 deletions
diff --git a/blktrace.c b/blktrace.c
index b03f7d1..2bb38ed 100644
--- a/blktrace.c
+++ b/blktrace.c
@@ -34,6 +34,7 @@
#include <sched.h>
#include <ctype.h>
#include <getopt.h>
+#include <sys/mman.h>
#include "blktrace.h"
@@ -126,6 +127,10 @@ struct thread_information {
int fd;
char fn[MAXPATHLEN + 64];
+ void *buf;
+ unsigned long buf_offset;
+ unsigned int buf_subbuf;
+ unsigned int sequence;
pthread_mutex_t *fd_lock;
int ofd;
@@ -152,6 +157,7 @@ static char *relay_path;
static char *output_name;
static int act_mask = ~0U;
static int kill_running_trace;
+static int use_mmap;
#define is_done() (*(volatile int *)(&done))
static volatile int done;
@@ -209,32 +215,87 @@ static void stop_all_traces(void)
stop_trace(dip);
}
-static void *extract_data(struct thread_information *tip, char *ofn, int nb)
+static int get_data_read(struct thread_information *tip, void *buf, int len)
{
- int ret, bytes_left;
- unsigned char *buf, *p;
+ char *p = buf;
+ int ret, bytes_left = len;
- buf = malloc(nb);
- p = buf;
- bytes_left = nb;
- while (bytes_left > 0) {
+ while (!is_done() && bytes_left > 0) {
ret = read(tip->fd, p, bytes_left);
- if (!ret)
- usleep(1000);
- else if (ret < 0) {
+ if (ret == len)
+ break;
+
+ if (ret < 0) {
perror(tip->fn);
- fprintf(stderr, "Thread %d extract_data %s failed\n",
+ fprintf(stderr,"Thread %d failed read of %s\n",
tip->cpu, tip->fn);
- free(buf);
exit_trace(1);
- return NULL;
+ } else if (ret > 0) {
+ fprintf(stderr,"Thread %d misread %s %d,%d\n",
+ tip->cpu, tip->fn, ret, len);
+ exit_trace(1);
} else {
p += ret;
bytes_left -= ret;
}
+
+ usleep(10000);
}
- return buf;
+ return 0;
+}
+
+static int get_data_mmap(struct thread_information *tip, void *buf, int len,
+ int check_magic)
+{
+ if (len > (BUF_SIZE * (tip->buf_subbuf + 1)) - tip->buf_offset) {
+ tip->buf_subbuf++;
+ if (tip->buf_subbuf == BUF_NR)
+ tip->buf_subbuf = 0;
+
+ tip->buf_offset = tip->buf_subbuf * BUF_SIZE;
+ }
+
+ while (!is_done()) {
+ struct blk_io_trace *t = buf;
+
+ memcpy(buf, tip->buf + tip->buf_offset, len);
+
+ if (!check_magic)
+ break;
+
+ if (CHECK_MAGIC(t) && t->sequence >= tip->sequence) {
+ tip->sequence = t->sequence;
+ break;
+ }
+
+ usleep(10000);
+ }
+
+ tip->buf_offset += len;
+ return 0;
+}
+
+static int get_data(struct thread_information *tip, void *buf, int len,
+ int check_magic)
+{
+ if (tip->buf)
+ return get_data_mmap(tip, buf, len, check_magic);
+ else
+ return get_data_read(tip, buf, len);
+}
+
+static void *extract_data(struct thread_information *tip, char *ofn, int nb)
+{
+ unsigned char *buf;
+
+ buf = malloc(nb);
+ if (!get_data(tip, buf, nb, 0))
+ return buf;
+
+ free(buf);
+ exit_trace(1);
+ return NULL;
}
static inline void tip_fd_unlock(struct thread_information *tip)
@@ -276,24 +337,19 @@ static void *extract(void *arg)
exit_trace(1);
}
+ if (use_mmap) {
+ tip->buf = mmap(NULL, BUF_SIZE * BUF_NR, PROT_READ,
+ MAP_PRIVATE | MAP_POPULATE, tip->fd, 0);
+ if (tip->buf == MAP_FAILED) {
+ perror("mmap");
+ exit_trace(1);
+ }
+ }
+
pdu_data = NULL;
while (!is_done()) {
- ret = read(tip->fd, &t, sizeof(t));
- if (ret != sizeof(t)) {
- if (ret < 0) {
- perror(tip->fn);
- fprintf(stderr,"Thread %d failed read of %s\n",
- tip->cpu, tip->fn);
- exit_trace(1);
- } else if (ret > 0) {
- fprintf(stderr,"Thread %d misread %s %d,%d\n",
- tip->cpu, tip->fn, ret, (int)sizeof(t));
- exit_trace(1);
- } else {
- usleep(10000);
- continue;
- }
- }
+ if (get_data(tip, &t, sizeof(t), 1))
+ break;
if (verify_trace(&t))
exit_trace(1);
@@ -322,6 +378,7 @@ static void *extract(void *arg)
ret = write(tip->ofd, pdu_data, pdu_len);
if (ret != pdu_len) {
perror("write pdu data");
+ tip_fd_unlock(tip);
exit_trace(1);
}
@@ -378,10 +435,14 @@ static int start_threads(struct device_information *dip)
static void close_thread(struct thread_information *tip)
{
+ if (tip->buf)
+ munmap(tip->buf, BUF_SIZE * BUF_NR);
+
if (tip->fd != -1)
close(tip->fd);
if (tip->ofd != -1)
close(tip->ofd);
+
tip->fd = tip->ofd = -1;
}