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[Qemu-devel] [throwaway PATCH] add fio plugin


From: Paolo Bonzini
Subject: [Qemu-devel] [throwaway PATCH] add fio plugin
Date: Tue, 13 Dec 2016 16:17:52 +0100

All of the infrastructure is a bit hackish, which is why I've marked
this as throwaway, but perhaps someone else would like to use it (or
even revive the libtool infrastructure so that it can be included
in QEMU).  I tested it with fio 2.8 and the master branch.

Support for driver options is minimal (only aio=native/threads :) so
if you want to use the null driver remember that the size should be
at most 1G (the default size of the null block device).

The plugin requires Stefan's polling patches, but it's easy to remove
the poll_max_ns option if desired.

Signed-off-by: Paolo Bonzini <address@hidden>
---
 configure                 |  15 +-
 contrib/fio/Makefile      |  62 +++++++
 contrib/fio/README        |  13 ++
 contrib/fio/fio.c         | 436 ++++++++++++++++++++++++++++++++++++++++++++++
 contrib/fio/qemu.fio      |  27 +++
 contrib/fio/uninclude.awk |  78 +++++++++
 6 files changed, 624 insertions(+), 7 deletions(-)

diff --git a/configure b/configure
index 3770d7c..2c844bc 100755
--- a/configure
+++ b/configure
@@ -1589,8 +1589,8 @@ static THREAD int tls_var;
 int main(void) { return tls_var; }
 
 EOF
-  if compile_prog "-fPIE -DPIE" "-pie"; then
-    QEMU_CFLAGS="-fPIE -DPIE $QEMU_CFLAGS"
+  if compile_prog "-fPIC -DPIC" "-pie"; then
+    QEMU_CFLAGS="-fPIC -DPIC $QEMU_CFLAGS"
     LDFLAGS="-pie $LDFLAGS"
     pie="yes"
     if compile_prog "" "-Wl,-z,relro -Wl,-z,now" ; then
@@ -1598,15 +1598,15 @@ EOF
     fi
   else
     if test "$pie" = "yes"; then
-      error_exit "PIE not available due to missing toolchain support"
+      error_exit "PIC not available due to missing toolchain support"
     else
-      echo "Disabling PIE due to missing toolchain support"
+      echo "Disabling PIC due to missing toolchain support"
       pie="no"
     fi
   fi
 
-  if compile_prog "-Werror -fno-pie" "-nopie"; then
-    CFLAGS_NOPIE="-fno-pie"
+  if compile_prog "-Werror -fno-pic -fno-pie" "-nopie"; then
+    CFLAGS_NOPIE="-fno-pic -fno-pie"
     LDFLAGS_NOPIE="-nopie"
   fi
 fi
@@ -6183,13 +6183,14 @@ fi
 
 # build tree in object directory in case the source is not in the current 
directory
 DIRS="tests tests/tcg tests/tcg/cris tests/tcg/lm32 tests/libqos 
tests/qapi-schema tests/tcg/xtensa tests/qemu-iotests"
-DIRS="$DIRS fsdev"
+DIRS="$DIRS fsdev contrib/fio"
 DIRS="$DIRS pc-bios/optionrom pc-bios/spapr-rtas pc-bios/s390-ccw"
 DIRS="$DIRS roms/seabios roms/vgabios"
 DIRS="$DIRS qapi-generated"
 FILES="Makefile tests/tcg/Makefile qdict-test-data.txt"
 FILES="$FILES tests/tcg/cris/Makefile tests/tcg/cris/.gdbinit"
 FILES="$FILES tests/tcg/lm32/Makefile tests/tcg/xtensa/Makefile po/Makefile"
+FILES="$FILES contrib/fio/Makefile"
 FILES="$FILES pc-bios/optionrom/Makefile pc-bios/keymaps"
 FILES="$FILES pc-bios/spapr-rtas/Makefile"
 FILES="$FILES pc-bios/s390-ccw/Makefile"
diff --git a/contrib/fio/Makefile b/contrib/fio/Makefile
new file mode 100644
index 0000000..3d47d5c
--- /dev/null
+++ b/contrib/fio/Makefile
@@ -0,0 +1,62 @@
+# -*- Mode: makefile -*-
+
+BUILD_DIR?=$(CURDIR)/../..
+
+include ../../config-host.mak
+include $(SRC_PATH)/rules.mak
+
+$(call set-vpath, $(SRC_PATH):$(SRC_PATH)/contrib/fio:$(CURDIR))
+
+PROGS=qemu.so
+
+all: $(PROGS)
+# Dummy command so that make thinks it has done something
+       @true
+
+QEMU_CFLAGS += -Wno-redundant-decls
+LIBS += $(LIBS_TOOLS)
+
+# We need two fio header files, but we don't want to include
+# fio's config-host.h because its #defined symbols conflict
+# with QEMU's own config-host.h.  In general we do not want to
+# have -I$(FIO_PATH) while compiling fio.o because the possible
+# conflicts are a mess.
+#
+# optgroup.h is tame and we can just copy it to the build directory,
+# but fio.h includes a lot of other header files, from both fio
+# itself and the system.  Therefore we preprocess it so that
+# fio's headers are merged into a single file, fio-qemu.h, while
+# system headers are left as #include directives.  Because the
+# preprocessing step removes all preprocessor conditionals,
+# there is no dependency left on fio's config-host.h file.
+#
+# While at it, we hack some symbols that conflict with QEMU's,
+# by prefixing them with a "FIO_" or "fio_" namespace.
+fio.o: fio-qemu.h fio-optgroup-qemu.h
+
+fio-optgroup-qemu.h:
+       cp $(FIO_PATH)/optgroup.h $@
+
+FIO_HACK_SYMBOLS=sed -e 's/\<JSON_/FIO_&/' -e 's/\<cpu_to_/fio_&/'
+fio-qemu.h:
+       $(CC) -dD -dI -C -E -o - -I$(FIO_PATH) $(QEMU_CFLAGS) \
+            -include $(FIO_PATH)/config-host.h $(FIO_PATH)/fio.h | \
+            awk -f $(SRC_PATH)/contrib/fio/uninclude.awk | \
+            $(FIO_HACK_SYMBOLS) > $@
+
+include $(SRC_PATH)/Makefile.objs
+dummy := $(call unnest-vars,../.., \
+               block-obj-y \
+               block-obj-m \
+               crypto-obj-y \
+               qom-obj-y \
+               io-obj-y)
+obj-y := fio.o $(block-obj-y) $(crypto-obj-y) $(io-obj-y) $(qom-obj-y)
+
+dummy := $(shell mkdir -p $(dir $(obj-y)))
+qemu.so: $(obj-y) ../../libqemuutil.a ../../libqemustub.a
+       $(call LINK, $^)
+
+clean: clean-target
+       rm -f *.a $(filter-out ../../%, $(obj-y))
+       rm -f $(shell find . -name '*.[od]')
diff --git a/contrib/fio/README b/contrib/fio/README
new file mode 100644
index 0000000..4aef2a0
--- /dev/null
+++ b/contrib/fio/README
@@ -0,0 +1,13 @@
+This is a plugin to test the QEMU block layer with fio,
+the flexible I/O tester.
+
+To build this plugin you have to:
+
+1) hack the configure file to use -fPIC instead of -fPIE
+
+2) configure qemu with --enable-pie
+
+3) build the plugin with
+
+       make qemu-img
+       make -C contrib/fio FIO_PATH=/path/to/fio/source
diff --git a/contrib/fio/fio.c b/contrib/fio/fio.c
new file mode 100644
index 0000000..229b71c
--- /dev/null
+++ b/contrib/fio/fio.c
@@ -0,0 +1,436 @@
+/*
+ * QEMU engine for fio
+ *
+ */
+#include "fio-qemu.h"
+#include "fio-optgroup-qemu.h"
+#include "qemu/osdep.h"
+#include "qemu/iov.h"
+#include "qapi/error.h"
+#include "qapi/qmp/qdict.h"
+#include "qapi/qmp/qstring.h"
+#include "block/aio.h"
+#include "block/qapi.h"
+#include "crypto/init.h"
+#include "sysemu/block-backend.h"
+
+#ifndef TD_ENG_FLAG_SHIFT
+#define io_ops_data io_ops->data
+#define io_ops_dlhandle io_ops->dlhandle
+#endif
+
+struct qemu_data {
+       AioContext *ctx;
+       unsigned int completed;
+       unsigned int to_submit;
+       struct io_u *aio_events[];
+};
+
+struct qemu_options {
+       void *pad;
+       const char *aio;
+       const char *format;
+       const char *driver;
+       unsigned int poll_max_ns;
+};
+
+static QemuMutex iothread_lock;
+
+static int str_aio_cb(void *data, const char *str)
+{
+       struct qemu_options *o = data;
+
+       if (!strcmp(str, "native") || !strcmp(str, "threads"))
+               o->aio = strdup(str);
+       else
+               return 1;
+
+       return 0;
+}
+
+static struct fio_option options[] = {
+       {
+               .name   = "qemu_driver",
+               .lname  = "QEMU block driver",
+               .type   = FIO_OPT_STR_STORE,
+               .off1   = offsetof(struct qemu_options, driver),
+               .category = FIO_OPT_C_ENGINE,
+               .group  = FIO_OPT_G_INVALID,
+       },
+       {
+               .name   = "qemu_format",
+               .lname  = "Image format",
+               .type   = FIO_OPT_STR_STORE,
+               .off1   = offsetof(struct qemu_options, format),
+               .category = FIO_OPT_C_ENGINE,
+               .group  = FIO_OPT_G_INVALID,
+       },
+       {
+               .name   = "qemu_aio",
+               .lname  = "Use native AIO",
+               .type   = FIO_OPT_STR_STORE,
+               .off1   = offsetof(struct qemu_options, aio),
+               .cb     = str_aio_cb,
+               .category = FIO_OPT_C_ENGINE,
+               .group  = FIO_OPT_G_INVALID,
+       },
+       {
+               .name   = "qemu_poll_max_ns",
+               .lname  = "QEMU polling period",
+               .type   = FIO_OPT_STR_SET,
+               .off1   = offsetof(struct qemu_options, poll_max_ns),
+               .category = FIO_OPT_C_ENGINE,
+               .group  = FIO_OPT_G_INVALID,
+       },
+       {
+               .name   = NULL,
+       },
+};
+
+static int fio_qemu_getevents(struct thread_data *td, unsigned int min,
+                             unsigned int max, const struct timespec *t)
+{
+       struct qemu_data *qd = td->io_ops_data;
+
+       /* TODO: set timer */
+       do
+               aio_poll(qd->ctx, true);
+       while (qd->completed < min);
+
+       return qd->completed;
+}
+
+static struct io_u *fio_qemu_event(struct thread_data *td, int event)
+{
+       struct qemu_data *qd = td->io_ops_data;
+
+       qd->completed--;
+       return qd->aio_events[event];
+}
+
+static inline BlockBackend *fio_qemu_get_blk(struct fio_file *file)
+{
+       return (BlockBackend *)(uintptr_t)(file->engine_data & ~1);
+}
+
+static inline bool fio_qemu_mark_plugged(struct fio_file *file)
+{
+       bool plugged = (file->engine_data & 1);
+       file->engine_data |= 1;
+       return plugged;
+}
+
+static inline bool fio_qemu_test_and_clear_plugged(struct fio_file *file)
+{
+       bool plugged = (file->engine_data & 1);
+       file->engine_data &= ~1;
+       return plugged;
+}
+
+static void fio_qemu_entry(void *opaque)
+{
+       struct io_u *io_u = opaque;
+       struct fio_file *file = io_u->file;
+       BlockBackend *blk = fio_qemu_get_blk(file);
+       struct iovec iov = { io_u->xfer_buf, io_u->xfer_buflen };
+
+       struct thread_data *td;
+       struct qemu_data *qd;
+       unsigned r;
+       int ret;
+
+       if (!fio_qemu_mark_plugged(io_u->file))
+               blk_io_plug(blk);
+
+       if (io_u->ddir == DDIR_READ) {
+               QEMUIOVector qiov;
+               qemu_iovec_init_external(&qiov, &iov, 1);
+               ret = blk_co_preadv(blk, io_u->offset, iov.iov_len, &qiov, 0);
+       } else if (io_u->ddir == DDIR_WRITE) {
+               QEMUIOVector qiov;
+               qemu_iovec_init_external(&qiov, &iov, 1);
+               ret = blk_co_pwritev(blk, io_u->offset, iov.iov_len, &qiov, 0);
+       } else if (io_u->ddir == DDIR_TRIM) {
+               ret = blk_co_pdiscard(blk, io_u->offset, iov.iov_len);
+       } else {
+               ret = blk_flush(blk);
+       }
+
+       if (!ret) {
+               io_u->resid = 0;
+               io_u->error = 0;
+       } else if (ret == -ECANCELED) {
+               io_u->resid = io_u->xfer_buflen;
+               io_u->error = 0;
+       } else {
+               io_u->error = -ret;
+       }
+
+       td = io_u->engine_data;
+       qd = td->io_ops_data;
+       r = qd->completed++;
+       qd->aio_events[r] = io_u;
+}
+
+static int fio_qemu_queue(struct thread_data *td,
+                             struct io_u *io_u)
+{
+       Coroutine *co;
+       struct qemu_data *qd;
+
+       fio_ro_check(td, io_u);
+
+       co = qemu_coroutine_create(fio_qemu_entry, io_u);
+       io_u->error = EINPROGRESS;
+       io_u->engine_data = td;
+       qemu_coroutine_enter(co);
+
+       qd = td->io_ops_data;
+       if (io_u->error == EINPROGRESS) {
+               /* Since we have a commit hook, we need to call io_u_queued()
+                * ourselves, but we don't really know if the backend actually
+                * does anything on blk_io_plug/unplug.  Calling it here is not
+                * exactly right if it does do something, but it saves the
+                * expense of walking the io_u's again in fio_qemu_commit.
+                */
+               io_u_queued(td, io_u);
+               io_u->error = 0;
+               qd->to_submit++;
+               return FIO_Q_QUEUED;
+       }
+
+       /* This I/O operation has completed.  If all of them are, fio will not
+        * call fio_qemu_commit, so unplug immediately.
+        */
+       qd->completed--;
+       if (qd->to_submit == 0) {
+               BlockBackend *blk = fio_qemu_get_blk(io_u->file);
+               fio_qemu_test_and_clear_plugged(io_u->file);
+               blk_io_unplug(blk);
+       }
+
+       return FIO_Q_COMPLETED;
+}
+
+static int fio_qemu_commit(struct thread_data *td)
+{
+       struct qemu_data *qd = td->io_ops_data;
+       struct fio_file *file;
+       int i;
+
+       for_each_file(td, file, i) {
+               if (fio_qemu_test_and_clear_plugged(file)) {
+                       BlockBackend *blk = fio_qemu_get_blk(file);
+                       blk_io_unplug(blk);
+               }
+       }
+       qd->to_submit = 0;
+
+       return 0;
+}
+
+static int fio_qemu_invalidate(struct thread_data *td, struct fio_file *file)
+{
+       return 0;
+}
+static void fio_qemu_cleanup(struct thread_data *td)
+{
+       struct qemu_data *qd = td->io_ops_data;
+
+       if (qd) {
+               aio_context_unref(qd->ctx);
+               free(qd);
+       }
+}
+
+static QDict *fio_qemu_opts(struct thread_data *td, struct fio_file *file)
+{
+       QDict *bs_opts;
+       struct qemu_options *o = td->eo;
+
+       bs_opts = qdict_new();
+       if (td_read(td) && read_only)
+               qdict_put(bs_opts, BDRV_OPT_READ_ONLY,
+                         qstring_from_str("on"));
+       qdict_put(bs_opts, BDRV_OPT_CACHE_DIRECT,
+                 qstring_from_str(td->o.odirect ? "on" : "off"));
+       if (o->format)
+               qdict_put(bs_opts, "format", qstring_from_str(o->format));
+
+       /* If no format is provided, but a driver is, skip the raw format.  */
+       if (o->driver)
+               qdict_put(bs_opts, !o->format ? "driver" : "file.driver",
+                         qstring_from_str(o->driver));
+
+
+       /* This is mostly a convenience, because the aio option of the file
+        * driver is commonly specified.
+        */
+       if (o->aio)
+               qdict_put(bs_opts, !o->format && o->driver ? "aio" : "file.aio",
+                         qstring_from_str(o->aio));
+
+       return bs_opts;
+}
+
+static int fio_qemu_get_file_size(struct thread_data *td, struct fio_file 
*file)
+{
+       Error *local_error = NULL;
+       BlockBackend *blk;
+       QDict *bs_opts;
+       ImageInfo *info;
+
+       bs_opts = fio_qemu_opts(td, file);
+       qemu_mutex_lock(&iothread_lock);
+       blk = blk_new_open(file->file_name, NULL, bs_opts, 0, &local_error);
+       if (local_error) {
+               struct qemu_options *o = td->eo;
+               if (!td->o.create_on_open || !td->o.allow_create)
+                       goto err;
+
+               error_free(local_error);
+               local_error = NULL;
+
+               bdrv_img_create(file->file_name, o->format ? : "raw", NULL, 
NULL,
+                               NULL, get_rand_file_size(td), 0, &local_error, 
false);
+               if (local_error)
+                       goto err;
+
+               bs_opts = fio_qemu_opts(td, file);
+               blk = blk_new_open(file->file_name, NULL, bs_opts, 0, 
&local_error);
+               if (local_error)
+                       goto err;
+       }
+
+       /* QDECREF(bs_opts); ??? */
+       bdrv_query_image_info(blk_bs(blk), &info, &local_error);
+       blk_unref(blk);
+       qemu_mutex_unlock(&iothread_lock);
+
+       file->real_file_size = info->virtual_size;
+       fio_file_set_size_known(file);
+       qapi_free_ImageInfo(info);
+
+       return 0;
+err:
+       qemu_mutex_unlock(&iothread_lock);
+       error_report_err(local_error);
+       return -EINVAL;
+}
+
+static void fio_qemu_setup_globals(void)
+{
+       qemu_init_main_loop(&error_abort);
+       qcrypto_init(&error_fatal);
+       module_call_init(MODULE_INIT_QOM);
+       bdrv_init();
+       qemu_mutex_init(&iothread_lock);
+}
+
+static int fio_qemu_setup(struct thread_data *td)
+{
+       static pthread_once_t fio_qemu_globals = PTHREAD_ONCE_INIT;
+       struct fio_file *file;
+       int i;
+
+       td->o.use_thread = 1;
+       pthread_once(&fio_qemu_globals, fio_qemu_setup_globals);
+
+        if (!td->o.file_size_low)
+               td->o.file_size_low = td->o.file_size_high =
+                       td->o.size / td->o.nr_files;
+
+       for_each_file(td, file, i) {
+               int ret;
+               dprint(FD_FILE, "get file size for %p/%d/%p\n", file, i,
+                                                               
file->file_name);
+
+               ret = fio_qemu_get_file_size(td, file);
+               if (ret < 0) {
+                       log_err("%s\n", strerror(-ret));
+                       return 1;
+               }
+       }
+
+       return 0;
+}
+
+static int fio_qemu_init(struct thread_data *td)
+{
+       size_t sz = sizeof(struct qemu_data) + td->o.iodepth * sizeof(struct 
io_u *);
+       struct qemu_data *qd = malloc(sz);
+       struct qemu_options *o = td->eo;
+       Error *local_error = NULL;
+
+       memset(qd, 0, sz);
+       qd->ctx = aio_context_new(&error_abort);
+       aio_context_set_poll_params(qd->ctx, o->poll_max_ns, 0, 0, 
&local_error);
+       if (local_error) {
+               error_report_err(local_error);
+               return 1;
+       }
+
+       /* dlclosing QEMU leaves a pthread_key behind.  We'd need RTLD_NODELETE,
+        * but fio does not use it.  Instead, just prevent fio from dlclosing.
+        */
+       td->io_ops_dlhandle = NULL;
+
+       td->io_ops_data = qd;
+       td->o.use_thread = 1;
+       return 0;
+}
+
+static int fio_qemu_open_file(struct thread_data *td, struct fio_file *file)
+{
+       struct qemu_data *qd = td->io_ops_data;
+       Error *local_error = NULL;
+       QDict *bs_opts;
+       BlockBackend *blk;
+
+       qemu_mutex_lock(&iothread_lock);
+       bs_opts = fio_qemu_opts(td, file);
+       blk = blk_new_open(file->file_name, NULL, bs_opts, 0, &local_error);
+       /* QDECREF(bs_opts); ??? */
+
+       if (local_error) {
+               error_report_err(local_error);
+               return -EINVAL;
+       }
+
+       blk_set_aio_context(blk, qd->ctx);
+       blk_set_enable_write_cache(blk, !td->o.sync_io);
+       qemu_mutex_unlock(&iothread_lock);
+
+       file->engine_data = (uintptr_t)blk;
+       td->o.open_files ++;
+       return 0;
+}
+
+static int fio_qemu_close_file(struct thread_data *td, struct fio_file *file)
+{
+       BlockBackend *blk = fio_qemu_get_blk(file);
+
+       if (blk) {
+               blk_unref(blk);
+               file->engine_data = 0;
+       }
+
+       return 0;
+}
+
+struct ioengine_ops ioengine = {
+       .name           = "qemu",
+       .version        = FIO_IOOPS_VERSION,
+       .init           = fio_qemu_init,
+       .queue          = fio_qemu_queue,
+       .commit         = fio_qemu_commit,
+       .getevents      = fio_qemu_getevents,
+       .event          = fio_qemu_event,
+       .invalidate     = fio_qemu_invalidate,
+       .cleanup        = fio_qemu_cleanup,
+       .setup          = fio_qemu_setup,
+       .open_file      = fio_qemu_open_file,
+       .close_file     = fio_qemu_close_file,
+       .options        = options,
+       .option_struct_size = sizeof(struct qemu_options),
+};
diff --git a/contrib/fio/qemu.fio b/contrib/fio/qemu.fio
new file mode 100644
index 0000000..09241c1
--- /dev/null
+++ b/contrib/fio/qemu.fio
@@ -0,0 +1,27 @@
+; Read 4 files with aio at different depths
+[global]
+ioengine=./qemu.so
+direct=1
+qemu_aio=native
+create_on_open=1
+rw=randread
+bs=128k
+filesize=128m
+runtime=10s
+time_based
+
+[file1]
+filename=file1
+iodepth=4
+
+[file2]
+filename=file2
+iodepth=32
+
+[file3]
+filename=file3
+iodepth=8
+
+[file4]
+filename=file4
+iodepth=16
diff --git a/contrib/fio/uninclude.awk b/contrib/fio/uninclude.awk
new file mode 100644
index 0000000..88afa59
--- /dev/null
+++ b/contrib/fio/uninclude.awk
@@ -0,0 +1,78 @@
+BEGIN {
+    # gcc strips #ifdef blocks, which removes the multiple-inclusion guard too.
+    # Repair with #pragma once.
+    print "#pragma once"
+}
+
+{
+    # Documentation says builtins are not printed by -dD, but reality 
disagrees.
+    if ($1 == "#" && $3 ~ "\"<built-in>\"") {
+        delete_until_hash = 1
+        next
+    }
+    if (delete_until_hash) {
+        if ($1 == "#") {
+            delete_until_hash = 0
+        } else {
+           next
+       }
+   }
+
+    # Handle the delete state: skip files included with <...> and -include,
+    # plus their nested includes
+    if (delete_depth) {
+        if ($1 == "#") {
+            if ($4 == "1") {
+                delete_depth++
+            } else if ($4 == "2") {
+                delete_depth--
+            }
+        }
+        if (delete_depth) {
+            next
+        } else {
+            # Out of delete state.  We are on a # directive, if necessary
+            # we can use it to set command_line again
+            command_line = 0
+        }
+    }
+
+    # Handle the command-line state: skip -D definitions and -included files
+    if ($1 == "#" && $3 == "\"<command-line>\"") {
+        command_line = 1
+    }
+
+    if (command_line) {
+        if ($1 == "#" && $4 == "1") {
+            # This is a -included file, go to the delete state
+            delete_depth = 1
+        }
+        next
+    }
+
+    if ($1 == "#include") {
+        if ($2 ~ /^</) {
+            print
+            # We printed the #include directive.  Now skip until the # line
+            # that enters the included file, and go to the delete state.
+            do {
+                getline
+            } while ($1 == "#" && $4 != "1")
+            if ($1 == "#" && $4 == "1") {
+                delete_depth = 1
+                next
+            }
+        } else {
+            # For local includes we include their content, so the #include
+            # directive must go.
+            next
+        }
+    }
+
+    # Remove line directives emitted by the preprocessor
+    if ($1 == "#") {
+        next
+    }
+
+    print
+}



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