Add support for the iomem_align option

This allows detailed control of the alignment of the IO buffers
that fio uses.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

diff --git a/HOWTO b/HOWTO
index f323c204d3c67be97e98926ae8efd0ae1d82314d..3107d3a15e6b4488dcd8626264b791d078459d1e 100644 (file)
--- a/HOWTO
+++ b/HOWTO
@@ -704,6 +704,15 @@ mem=str            Fio can use various types of memory as the io unit buffer.
                location should point there. So if it's mounted in /huge,
                you would use mem=mmaphuge:/huge/somefile.
 
+iomem_align=int        This indiciates the memory alignment of the IO memory buffers.
+               Note that the given alignment is applied to the first IO unit
+               buffer, if using iodepth the alignment of the following buffers
+               are given by the bs used. In other words, if using a bs that is
+               a multiple of the page sized in the system, all buffers will
+               be aligned to this value. If using a bs that is not page
+               aligned, the alignment of subsequent IO memory buffers is the
+               sum of the iomem_align and bs used.
+
 hugepage-size=int
                Defines the size of a huge page. Must at least be equal
                to the system setting, see /proc/meminfo. Defaults to 4MiB.

diff --git a/fio.1 b/fio.1
index fc055e4d8cb2dbd1e4b763ffd316aedcba4d667b..aa7b9d6767ed9a0136a2282c133878383356d143 100644 (file)
--- a/fio.1
+++ b/fio.1
@@ -512,6 +512,15 @@ the system must have free huge pages allocated.  \fBmmaphuge\fR also needs to
 have hugetlbfs mounted, and \fIfile\fR must point there.
 .RE
 .TP
+.BI iomem_align \fR=\fPint
+This indiciates the memory alignment of the IO memory buffers. Note that the
+given alignment is applied to the first IO unit buffer, if using \fBiodepth\fR
+the alignment of the following buffers are given by the \fBbs\fR used. In
+other words, if using a \fBbs\fR that is a multiple of the page sized in the
+system, all buffers will be aligned to this value. If using a \fBbs\fR that
+is not page aligned, the alignment of subsequent IO memory buffers is the
+sum of the \fBiomem_align\fR and \fBbs\fR used.
+.TP
 .BI hugepage\-size \fR=\fPint
 Defines the size of a huge page.  Must be at least equal to the system setting.
 Should be a multiple of 1MiB. Default: 4MiB.

diff --git a/fio.c b/fio.c
index 4927f1c6142fe078de0176f708ad57a34a8feec3..63d9a1b7ab434ca4eba416ab2fe71bbc9e71385a 100644 (file)
--- a/fio.c
+++ b/fio.c
@@ -42,7 +42,8 @@
 
 unsigned long page_mask;
 unsigned long page_size;
-#define ALIGN(buf)     \
+
+#define PAGE_ALIGN(buf)        \
        (char *) (((unsigned long) (buf) + page_mask) & ~page_mask)
 
 int groupid = 0;
@@ -790,8 +791,8 @@ static int init_io_u(struct thread_data *td)
        if (allocate_io_mem(td))
                return 1;
 
-       if (td->o.odirect)
-               p = ALIGN(td->orig_buffer);
+       if (td->o.mem_align)
+               p = PAGE_ALIGN(td->orig_buffer) + td->o.mem_align;
        else
                p = td->orig_buffer;
 
@@ -811,9 +812,11 @@ static int init_io_u(struct thread_data *td)
                io_u = ptr;
                memset(io_u, 0, sizeof(*io_u));
                INIT_FLIST_HEAD(&io_u->list);
+               dprint(FD_MEM, "io_u alloc %p, index %u\n", io_u, i);
 
                if (!(td->io_ops->flags & FIO_NOIO)) {
                        io_u->buf = p + max_bs * i;
+                       dprint(FD_MEM, "io_u %p, mem %p\n", io_u, io_u->buf);
 
                        if (td_write(td) && !td->o.refill_buffers)
                                io_u_fill_buffer(td, io_u, max_bs);

diff --git a/fio.h b/fio.h
index 71ae71db2c876749e1445996a8a980d8aafe0253..b19101c20a4924892610bd78b0f6d645f3b93e9b 100644 (file)
--- a/fio.h
+++ b/fio.h
@@ -202,6 +202,7 @@ struct thread_options {
        unsigned long long zone_size;
        unsigned long long zone_skip;
        enum fio_memtype mem_type;
+       unsigned int mem_align;
 
        unsigned int stonewall;
        unsigned int new_group;
@@ -655,4 +656,9 @@ static inline int should_check_rate(struct thread_data *td,
        return ret;
 }
 
+static inline int is_power_of_2(unsigned int val)
+{
+       return (val != 0 && ((val & (val - 1)) == 0));
+}
+
 #endif

diff --git a/init.c b/init.c
index 02e544a004290130e56a5d30ab430514eaeeb5a8..84c312f9d2194cc878dff29137003bf0d0f05ee5 100644 (file)
--- a/init.c
+++ b/init.c
@@ -367,6 +367,14 @@ static int fixup_options(struct thread_data *td)
        if (td->o.pre_read)
                td->o.invalidate_cache = 0;
 
+       if (td->o.mem_align) {
+               if (td->o.odirect && !is_power_of_2(td->o.mem_align)) {
+                       log_err("fio: given IO mem alignment conflicts with"
+                                       " direct=1. Resetting.\n");
+                       td->o.mem_align = page_mask;
+               }
+       }
+                       
        return 0;
 }
 

diff --git a/io_u.c b/io_u.c
index 41b5cdbb04894192cb06e2d86a49bdf28d48be9d..2e9dac0db6b4aa0adae673a3b21d26173e48da3e 100644 (file)
--- a/io_u.c
+++ b/io_u.c
@@ -231,11 +231,6 @@ static int get_next_offset(struct thread_data *td, struct io_u *io_u)
        return 0;
 }
 
-static inline int is_power_of_2(unsigned int val)
-{
-       return (val != 0 && ((val & (val - 1)) == 0));
-}
-
 static unsigned int get_next_buflen(struct thread_data *td, struct io_u *io_u)
 {
        const int ddir = io_u->ddir;

diff --git a/memory.c b/memory.c
index d3ef2cba9adda00bf9ab4f8d7bff9a7a47889665..00339e42663f25522ca1269c35883610a0d1e552 100644 (file)
--- a/memory.c
+++ b/memory.c
@@ -188,8 +188,12 @@ int allocate_io_mem(struct thread_data *td)
                return 0;
 
        total_mem = td->orig_buffer_size;
-       if (td->o.odirect)
+
+       if (td->o.odirect || td->o.mem_align) {
                total_mem += page_mask;
+               if (td->o.mem_align && td->o.mem_align > page_size)
+                       total_mem += td->o.mem_align - page_size;
+       }
 
        if (td->o.mem_type == MEM_MALLOC)
                ret = alloc_mem_malloc(td, total_mem);

diff --git a/options.c b/options.c
index 394472a4dadf61512e6c49f8495f97f248b357f5..7135231eefeed59b73cf720c73aab14c5c66a3c8 100644 (file)
--- a/options.c
+++ b/options.c
@@ -1036,6 +1036,16 @@ static struct fio_option options[] = {
 #endif
                  },
        },
+       {
+               .name   = "iomem_align",
+               .alias  = "mem_align",
+               .type   = FIO_OPT_INT,
+               .off1   = td_var_offset(mem_align),
+               .minval = 0,
+               .help   = "IO memory buffer offset alignment",
+               .def    = "0",
+               .parent = "iomem",
+       },
        {
                .name   = "verify",
                .type   = FIO_OPT_STR,