* [PATCH] fio: Add advise THP option to mmap engine
@ 2019-04-17 21:28 Keith Busch
2019-04-17 22:01 ` Jens Axboe
0 siblings, 1 reply; 3+ messages in thread
From: Keith Busch @ 2019-04-17 21:28 UTC (permalink / raw)
To: Jens Axboe, linux-block; +Cc: Keith Busch
The transparent hugepage Linux-specific memory advisory has potentially
significant implications for how the memory management behaves. Add a
new mmap specific option that enables private TLP mmap mode when set so
we can test running fio with anonymous memory (i.e. mmap /dev/zero).
Signed-off-by: Keith Busch <keith.busch@intel.com>
---
engines/mmap.c | 39 ++++++++++++++++++++++++++++++++++++---
optgroup.h | 2 ++
2 files changed, 38 insertions(+), 3 deletions(-)
diff --git a/engines/mmap.c b/engines/mmap.c
index 308b4665..7bca6c20 100644
--- a/engines/mmap.c
+++ b/engines/mmap.c
@@ -11,6 +11,7 @@
#include <sys/mman.h>
#include "../fio.h"
+#include "../optgroup.h"
#include "../verify.h"
/*
@@ -26,6 +27,26 @@ struct fio_mmap_data {
off_t mmap_off;
};
+struct mmap_options {
+ void *pad;
+ unsigned int thp;
+};
+
+static struct fio_option options[] = {
+ {
+ .name = "thp",
+ .lname = "Transparent Huge Pages",
+ .type = FIO_OPT_INT,
+ .off1 = offsetof(struct mmap_options, thp),
+ .help = "Memory Advise Huge Page",
+ .category = FIO_OPT_C_ENGINE,
+ .group = FIO_OPT_G_MMAP,
+ },
+ {
+ .name = NULL,
+ },
+};
+
static bool fio_madvise_file(struct thread_data *td, struct fio_file *f,
size_t length)
@@ -54,7 +75,8 @@ static int fio_mmap_file(struct thread_data *td, struct fio_file *f,
size_t length, off_t off)
{
struct fio_mmap_data *fmd = FILE_ENG_DATA(f);
- int flags = 0;
+ struct mmap_options *o = td->eo;
+ int flags = 0, shared = MAP_SHARED;
if (td_rw(td) && !td->o.verify_only)
flags = PROT_READ | PROT_WRITE;
@@ -66,7 +88,12 @@ static int fio_mmap_file(struct thread_data *td, struct fio_file *f,
} else
flags = PROT_READ;
- fmd->mmap_ptr = mmap(NULL, length, flags, MAP_SHARED, f->fd, off);
+#if FIO_OS==os_linux
+ if (o->thp)
+ shared = MAP_PRIVATE;
+#endif
+
+ fmd->mmap_ptr = mmap(NULL, length, flags, shared, f->fd, off);
if (fmd->mmap_ptr == MAP_FAILED) {
fmd->mmap_ptr = NULL;
td_verror(td, errno, "mmap");
@@ -146,6 +173,7 @@ static int fio_mmapio_prep(struct thread_data *td, struct io_u *io_u)
{
struct fio_file *f = io_u->file;
struct fio_mmap_data *fmd = FILE_ENG_DATA(f);
+ struct mmap_options *o = td->eo;
int ret;
/*
@@ -170,10 +198,13 @@ static int fio_mmapio_prep(struct thread_data *td, struct io_u *io_u)
if (ret)
return ret;
}
-
done:
io_u->mmap_data = fmd->mmap_ptr + io_u->offset - fmd->mmap_off -
f->file_offset;
+#if FIO_OS==os_linux
+ if (o->thp)
+ madvise(io_u->mmap_data, fmd->mmap_sz, MADV_HUGEPAGE);
+#endif
return 0;
}
@@ -275,6 +306,8 @@ static struct ioengine_ops ioengine = {
.close_file = fio_mmapio_close_file,
.get_file_size = generic_get_file_size,
.flags = FIO_SYNCIO | FIO_NOEXTEND,
+ .options = options,
+ .option_struct_size = sizeof(struct mmap_options),
};
static void fio_init fio_mmapio_register(void)
diff --git a/optgroup.h b/optgroup.h
index adf4d09b..bf1bb036 100644
--- a/optgroup.h
+++ b/optgroup.h
@@ -61,6 +61,7 @@ enum opt_category_group {
__FIO_OPT_G_MTD,
__FIO_OPT_G_HDFS,
__FIO_OPT_G_SG,
+ __FIO_OPT_G_MMAP,
__FIO_OPT_G_NR,
FIO_OPT_G_RATE = (1ULL << __FIO_OPT_G_RATE),
@@ -97,6 +98,7 @@ enum opt_category_group {
FIO_OPT_G_MTD = (1ULL << __FIO_OPT_G_MTD),
FIO_OPT_G_HDFS = (1ULL << __FIO_OPT_G_HDFS),
FIO_OPT_G_SG = (1ULL << __FIO_OPT_G_SG),
+ FIO_OPT_G_MMAP = (1ULL << __FIO_OPT_G_MMAP),
FIO_OPT_G_INVALID = (1ULL << __FIO_OPT_G_NR),
};
--
2.14.4
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] fio: Add advise THP option to mmap engine
2019-04-17 22:01 ` Jens Axboe
@ 2019-04-17 22:01 ` Keith Busch
0 siblings, 0 replies; 3+ messages in thread
From: Keith Busch @ 2019-04-17 22:01 UTC (permalink / raw)
To: Jens Axboe; +Cc: linux-block
On Wed, Apr 17, 2019 at 04:01:28PM -0600, Jens Axboe wrote:
> On 4/17/19 3:28 PM, Keith Busch wrote:
> > The transparent hugepage Linux-specific memory advisory has potentially
> > significant implications for how the memory management behaves. Add a
> > new mmap specific option that enables private TLP mmap mode when set so
> > we can test running fio with anonymous memory (i.e. mmap /dev/zero).
>
> I'm fine with this, but the usual approach to platform stuff like this
> is to have
>
> #define FIO_HAVE_THP
>
> or similar in the os/os-linux.h file and then have:
>
> #if FIO_OS==os_linux
> if (o->thp)
> madvise(io_u->mmap_data, fmd->mmap_sz, MADV_HUGEPAGE);
> #endif
>
> #if defined(FIO_HAVE_THP)
> ...
> #endif
>
> instead. Since we need MADV_HUGEPAGE as well, might even make sense to
> just have this be a configure check instead...
Sounds good. I like to fit in with the local customs, so will take
another shot at this.
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] fio: Add advise THP option to mmap engine
2019-04-17 21:28 [PATCH] fio: Add advise THP option to mmap engine Keith Busch
@ 2019-04-17 22:01 ` Jens Axboe
2019-04-17 22:01 ` Keith Busch
0 siblings, 1 reply; 3+ messages in thread
From: Jens Axboe @ 2019-04-17 22:01 UTC (permalink / raw)
To: Keith Busch, linux-block
On 4/17/19 3:28 PM, Keith Busch wrote:
> The transparent hugepage Linux-specific memory advisory has potentially
> significant implications for how the memory management behaves. Add a
> new mmap specific option that enables private TLP mmap mode when set so
> we can test running fio with anonymous memory (i.e. mmap /dev/zero).
I'm fine with this, but the usual approach to platform stuff like this
is to have
#define FIO_HAVE_THP
or similar in the os/os-linux.h file and then have:
#if FIO_OS==os_linux
if (o->thp)
madvise(io_u->mmap_data, fmd->mmap_sz, MADV_HUGEPAGE);
#endif
#if defined(FIO_HAVE_THP)
...
#endif
instead. Since we need MADV_HUGEPAGE as well, might even make sense to
just have this be a configure check instead...
--
Jens Axboe
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2019-04-17 22:07 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2019-04-17 21:28 [PATCH] fio: Add advise THP option to mmap engine Keith Busch
2019-04-17 22:01 ` Jens Axboe
2019-04-17 22:01 ` Keith Busch
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