Parse options only, don't start any I/O.
+.. option:: --merge-blktrace-only
+
+ Merge blktraces only, don't start any I/O.
+
.. option:: --output=filename
Write output to file `filename`.
will be read at once. If selected true, input from iolog will be read
gradually. Useful when iolog is very large, or it is generated.
+.. option:: merge_blktrace_file=str
+
+ When specified, rather than replaying the logs passed to :option:`read_iolog`,
+ the logs go through a merge phase which aggregates them into a single
+ blktrace. The resulting file is then passed on as the :option:`read_iolog`
+ parameter. The intention here is to make the order of events consistent.
+ This limits the influence of the scheduler compared to replaying multiple
+ blktraces via concurrent jobs.
+
.. option:: replay_no_stall=bool
When replaying I/O with :option:`read_iolog` the default behavior is to
**trim**
Trim the given file from the given `offset` for `length` bytes.
+
+I/O Replay - Merging Traces
+---------------------------
+
+Colocation is a common practice used to get the most out of a machine.
+Knowing which workloads play nicely with each other and which ones don't is
+a much harder task. While fio can replay workloads concurrently via multiple
+jobs, it leaves some variability up to the scheduler making results harder to
+reproduce. Merging is a way to make the order of events consistent.
+
+Merging is integrated into I/O replay and done when a
+:option:`merge_blktrace_file` is specified. The list of files passed to
+:option:`read_iolog` go through the merge process and output a single file
+stored to the specified file. The output file is passed on as if it were the
+only file passed to :option:`read_iolog`. An example would look like::
+
+ $ fio --read_iolog="<file1>:<file2>" --merge_blktrace_file="<output_file>"
+
+Creating only the merged file can be done by passing the command line argument
+:option:`merge-blktrace-only`.
+
+
CPU idleness profiling
----------------------
fifo_free(fifo);
return false;
}
+
+static int find_earliest_io(struct blktrace_cursor *bcs, int nr_logs)
+{
+ __u64 time = ~(__u64)0;
+ int idx = 0, i;
+
+ for (i = 0; i < nr_logs; i++) {
+ if (bcs[i].t.time < time) {
+ time = bcs[i].t.time;
+ idx = i;
+ }
+ }
+
+ return idx;
+}
+
+static void merge_finish_file(struct blktrace_cursor *bcs, int i, int *nr_logs)
+{
+ *nr_logs -= 1;
+
+ /* close file */
+ fifo_free(bcs[i].fifo);
+ close(bcs[i].fd);
+
+ /* keep active files contiguous */
+ memmove(&bcs[i], &bcs[*nr_logs], sizeof(bcs[i]));
+}
+
+static int read_trace(struct thread_data *td, struct blktrace_cursor *bc)
+{
+ int ret = 0;
+ struct blk_io_trace *t = &bc->t;
+
+read_skip:
+ /* read an io trace */
+ ret = trace_fifo_get(td, bc->fifo, bc->fd, t, sizeof(*t));
+ if (ret <= 0) {
+ return ret;
+ } else if (ret < (int) sizeof(*t)) {
+ log_err("fio: short fifo get\n");
+ return -1;
+ }
+
+ if (bc->swap)
+ byteswap_trace(t);
+
+ /* skip over actions that fio does not care about */
+ if ((t->action & 0xffff) != __BLK_TA_QUEUE ||
+ t_get_ddir(t) == DDIR_INVAL) {
+ ret = discard_pdu(td, bc->fifo, bc->fd, t);
+ if (ret < 0) {
+ td_verror(td, ret, "blktrace lseek");
+ return ret;
+ } else if (t->pdu_len != ret) {
+ log_err("fio: discarded %d of %d\n", ret,
+ t->pdu_len);
+ return -1;
+ }
+ goto read_skip;
+ }
+
+ return ret;
+}
+
+static int write_trace(FILE *fp, struct blk_io_trace *t)
+{
+ /* pdu is not used so just write out only the io trace */
+ t->pdu_len = 0;
+ return fwrite((void *)t, sizeof(*t), 1, fp);
+}
+
+int merge_blktrace_iologs(struct thread_data *td)
+{
+ int nr_logs = get_max_str_idx(td->o.read_iolog_file);
+ struct blktrace_cursor *bcs = malloc(sizeof(struct blktrace_cursor) *
+ nr_logs);
+ struct blktrace_cursor *bc;
+ FILE *merge_fp;
+ char *str, *ptr, *name, *merge_buf;
+ int i, ret;
+
+ /* setup output file */
+ merge_fp = fopen(td->o.merge_blktrace_file, "w");
+ merge_buf = malloc(128 * 1024);
+ ret = setvbuf(merge_fp, merge_buf, _IOFBF, 128 * 1024);
+ if (ret)
+ goto err_out_file;
+
+ /* setup input files */
+ str = ptr = strdup(td->o.read_iolog_file);
+ nr_logs = 0;
+ for (i = 0; (name = get_next_str(&ptr)) != NULL; i++) {
+ bcs[i].fd = open(name, O_RDONLY);
+ if (bcs[i].fd < 0) {
+ log_err("fio: could not open file: %s\n", name);
+ ret = bcs[i].fd;
+ goto err_file;
+ }
+ bcs[i].fifo = fifo_alloc(TRACE_FIFO_SIZE);
+ nr_logs++;
+
+ if (!is_blktrace(name, &bcs[i].swap)) {
+ log_err("fio: file is not a blktrace: %s\n", name);
+ goto err_file;
+ }
+
+ ret = read_trace(td, &bcs[i]);
+ if (ret < 0) {
+ goto err_file;
+ } else if (!ret) {
+ merge_finish_file(bcs, i, &nr_logs);
+ i--;
+ }
+ }
+ free(str);
+
+ /* merge files */
+ while (nr_logs) {
+ i = find_earliest_io(bcs, nr_logs);
+ bc = &bcs[i];
+ /* skip over the pdu */
+ ret = discard_pdu(td, bc->fifo, bc->fd, &bc->t);
+ if (ret < 0) {
+ td_verror(td, ret, "blktrace lseek");
+ goto err_file;
+ } else if (bc->t.pdu_len != ret) {
+ log_err("fio: discarded %d of %d\n", ret,
+ bc->t.pdu_len);
+ goto err_file;
+ }
+
+ ret = write_trace(merge_fp, &bc->t);
+ ret = read_trace(td, bc);
+ if (ret < 0)
+ goto err_file;
+ else if (!ret)
+ merge_finish_file(bcs, i, &nr_logs);
+ }
+
+ /* set iolog file to read from the newly merged file */
+ td->o.read_iolog_file = td->o.merge_blktrace_file;
+ ret = 0;
+
+err_file:
+ /* cleanup */
+ for (i = 0; i < nr_logs; i++) {
+ fifo_free(bcs[i].fifo);
+ close(bcs[i].fd);
+ }
+err_out_file:
+ fflush(merge_fp);
+ fclose(merge_fp);
+ free(bcs);
+
+ return ret;
+}
#ifndef FIO_BLKTRACE_H
#define FIO_BLKTRACE_H
+
#ifdef FIO_HAVE_BLKTRACE
+#include "blktrace_api.h"
+
+struct blktrace_cursor {
+ struct fifo *fifo; // fifo queue for reading
+ int fd; // blktrace file
+ struct blk_io_trace t; // current io trace
+ int swap; // bitwise reverse required
+};
+
bool is_blktrace(const char *, int *);
bool load_blktrace(struct thread_data *, const char *, int);
+int merge_blktrace_iologs(struct thread_data *td);
#else
free(o->mmapfile);
free(o->read_iolog_file);
free(o->write_iolog_file);
+ free(o->merge_blktrace_file);
free(o->bw_log_file);
free(o->lat_log_file);
free(o->iops_log_file);
string_to_cpu(&o->mmapfile, top->mmapfile);
string_to_cpu(&o->read_iolog_file, top->read_iolog_file);
string_to_cpu(&o->write_iolog_file, top->write_iolog_file);
+ string_to_cpu(&o->merge_blktrace_file, top->merge_blktrace_file);
string_to_cpu(&o->bw_log_file, top->bw_log_file);
string_to_cpu(&o->lat_log_file, top->lat_log_file);
string_to_cpu(&o->iops_log_file, top->iops_log_file);
string_to_net(top->mmapfile, o->mmapfile);
string_to_net(top->read_iolog_file, o->read_iolog_file);
string_to_net(top->write_iolog_file, o->write_iolog_file);
+ string_to_net(top->merge_blktrace_file, o->merge_blktrace_file);
string_to_net(top->bw_log_file, o->bw_log_file);
string_to_net(top->lat_log_file, o->lat_log_file);
string_to_net(top->iops_log_file, o->iops_log_file);
.BI \-\-parse\-only
Parse options only, don't start any I/O.
.TP
+.BI \-\-merge\-blktrace\-only
+Merge blktraces only, don't start any I/O.
+.TP
.BI \-\-output \fR=\fPfilename
Write output to \fIfilename\fR.
.TP
be read at once. If selected true, input from iolog will be read gradually.
Useful when iolog is very large, or it is generated.
.TP
+.BI merge_blktrace_file \fR=\fPstr
+When specified, rather than replaying the logs passed to \fBread_iolog\fR,
+the logs go through a merge phase which aggregates them into a single blktrace.
+The resulting file is then passed on as the \fBread_iolog\fR parameter. The
+intention here is to make the order of events consistent. This limits the
+influence of the scheduler compared to replaying multiple blktraces via
+concurrent jobs.
+.TP
.BI replay_no_stall \fR=\fPbool
When replaying I/O with \fBread_iolog\fR the default behavior is to
attempt to respect the timestamps within the log and replay them with the
Trim the given file from the given `offset' for `length' bytes.
.RE
.RE
+.SH I/O REPLAY \- MERGING TRACES
+Colocation is a common practice used to get the most out of a machine.
+Knowing which workloads play nicely with each other and which ones don't is
+a much harder task. While fio can replay workloads concurrently via multiple
+jobs, it leaves some variability up to the scheduler making results harder to
+reproduce. Merging is a way to make the order of events consistent.
+.P
+Merging is integrated into I/O replay and done when a \fBmerge_blktrace_file\fR
+is specified. The list of files passed to \fBread_iolog\fR go through the merge
+process and output a single file stored to the specified file. The output file is
+passed on as if it were the only file passed to \fBread_iolog\fR. An example would
+look like:
+.RS
+.P
+$ fio \-\-read_iolog="<file1>:<file2>" \-\-merge_blktrace_file="<output_file>"
+.RE
+.P
+Creating only the merged file can be done by passing the command line argument
+\fBmerge-blktrace-only\fR.
.SH CPU IDLENESS PROFILING
In some cases, we want to understand CPU overhead in a test. For example, we
test patches for the specific goodness of whether they reduce CPU usage.
#include "idletime.h"
#include "filelock.h"
#include "steadystate.h"
+#include "blktrace.h"
#include "oslib/getopt.h"
#include "oslib/strcasestr.h"
static int max_jobs = FIO_MAX_JOBS;
static int dump_cmdline;
static int parse_only;
+static int merge_blktrace_only;
static struct thread_data def_thread;
struct thread_data *threads = NULL;
.has_arg = required_argument,
.val = 'K',
},
+ {
+ .name = (char *) "merge-blktrace-only",
+ .has_arg = no_argument,
+ .val = 'A' | FIO_CLIENT_FLAG,
+ },
{
.name = NULL,
},
if (td_steadystate_init(td))
goto err;
+ if (o->merge_blktrace_file && !merge_blktrace_iologs(td))
+ goto err;
+
+ if (merge_blktrace_only) {
+ put_job(td);
+ return 0;
+ }
+
/*
* recurse add identical jobs, clear numjobs and stonewall options
* as they don't apply to sub-jobs
printf(" --debug=options\tEnable debug logging. May be one/more of:\n");
show_debug_categories();
printf(" --parse-only\t\tParse options only, don't start any IO\n");
+ printf(" --merge-blktrace-only\tMerge blktraces only, don't start any IO\n");
printf(" --output\t\tWrite output to file\n");
printf(" --bandwidth-log\tGenerate aggregate bandwidth logs\n");
printf(" --minimal\t\tMinimal (terse) output\n");
}
trigger_timeout /= 1000000;
break;
+
+ case 'A':
+ did_arg = true;
+ merge_blktrace_only = 1;
+ break;
case '?':
log_err("%s: unrecognized option '%s'\n", argv[0],
argv[optind - 1]);
.category = FIO_OPT_C_IO,
.group = FIO_OPT_G_IOLOG,
},
+ {
+ .name = "merge_blktrace_file",
+ .lname = "Merged blktrace output filename",
+ .type = FIO_OPT_STR_STORE,
+ .off1 = offsetof(struct thread_options, merge_blktrace_file),
+ .help = "Merged blktrace output filename",
+ .category = FIO_OPT_C_IO,
+ .group = FIO_OPT_G_IOLOG,
+ },
{
.name = "exec_prerun",
.lname = "Pre-execute runnable",
};
enum {
- FIO_SERVER_VER = 74,
+ FIO_SERVER_VER = 75,
FIO_SERVER_MAX_FRAGMENT_PDU = 1024,
FIO_SERVER_MAX_CMD_MB = 2048,
char *read_iolog_file;
bool read_iolog_chunked;
char *write_iolog_file;
+ char *merge_blktrace_file;
unsigned int write_bw_log;
unsigned int write_lat_log;
uint8_t read_iolog_file[FIO_TOP_STR_MAX];
uint8_t write_iolog_file[FIO_TOP_STR_MAX];
+ uint8_t merge_blktrace_file[FIO_TOP_STR_MAX];
uint32_t write_bw_log;
uint32_t write_lat_log;
projects / fio.git / commitdiff