diff options
Diffstat (limited to 'blktrace.c')
| -rw-r--r-- | blktrace.c | 75 |
1 files changed, 62 insertions, 13 deletions
@@ -8,6 +8,59 @@ #include "fio.h" #include "blktrace_api.h" +#define TRACE_FIFO_SIZE (sizeof(struct blk_io_trace) * 1000) + +/* + * fifo refill frontend, to avoid reading data in trace sized bites + */ +static int refill_fifo(struct thread_data *td, struct fifo *fifo, int fd) +{ + char buf[TRACE_FIFO_SIZE]; + unsigned int total, left; + void *ptr; + int ret; + + total = 0; + ptr = buf; + while (total < TRACE_FIFO_SIZE) { + left = TRACE_FIFO_SIZE - total; + + ret = read(fd, ptr, left); + if (ret < 0) { + td_verror(td, errno, "read blktrace file"); + return -1; + } else if (!ret) + break; + + fifo_put(fifo, ptr, ret); + ptr += ret; + total += ret; + } + + return 0; +} + +/* + * Retrieve 'len' bytes from the fifo, refilling if necessary. + */ +static int trace_fifo_get(struct thread_data *td, struct fifo *fifo, int fd, + void *buf, unsigned int len) +{ + int ret; + + if (fifo_len(fifo) >= len) + return fifo_get(fifo, buf, len); + + ret = refill_fifo(td, fifo, fd); + if (ret < 0) + return ret; + + if (fifo_len(fifo) < len) + return 0; + + return fifo_get(fifo, buf, len); +} + /* * Just discard the pdu by seeking past it. */ @@ -120,6 +173,7 @@ int load_blktrace(struct thread_data *td, const char *filename) unsigned long ios[2]; unsigned int cpu; unsigned int rw_bs[2]; + struct fifo *fifo; int fd; fd = open(filename, O_RDONLY); @@ -128,6 +182,8 @@ int load_blktrace(struct thread_data *td, const char *filename) return 1; } + fifo = fifo_alloc(TRACE_FIFO_SIZE); + td->o.size = 0; cpu = 0; @@ -135,22 +191,15 @@ int load_blktrace(struct thread_data *td, const char *filename) ios[0] = ios[1] = 0; rw_bs[0] = rw_bs[1] = 0; do { - /* - * Once this is working fully, I'll add a layer between - * here and read to cache trace data. Then we can avoid - * doing itsy bitsy reads, but instead pull in a larger - * chunk of data at the time. - */ - int ret = read(fd, &t, sizeof(t)); + int ret = trace_fifo_get(td, fifo, fd, &t, sizeof(t)); - if (ret < 0) { - td_verror(td, errno, "read blktrace file"); + if (ret < 0) goto err; - } else if (!ret) { + else if (!ret) + break; + else if (ret < (int) sizeof(t)) { + log_err("fio: short fifo get\n"); break; - } else if (ret != sizeof(t)) { - log_err("fio: short read on blktrace file\n"); - goto err; } if ((t.magic & 0xffffff00) != BLK_IO_TRACE_MAGIC) { |