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authorDave Barach <dbarach@cisco.com>2017-08-02 13:56:13 -0400
committerFlorin Coras <florin.coras@gmail.com>2017-08-10 14:34:31 +0000
commit818eb54de01459ed3d823f8a9781bbed0845db82 (patch)
treeb3ec3cbfb20ae371a648e9c8f5a7aaaa027b457f /src/svm
parentef5dd4f2aec6df1b58aa8d07493acf486eccf802 (diff)
Improve the svm fifo allocator
- Round up requested fifo size to the next power of two - Maintain per-segment power-of-two freelists - Allocate fifos in chunks, to amortize alignment overhead - Detach builtin test client application after each run so we can use different fifo sizes each time - Be more suspicious of session / application indices Useful prep work for dynamically resizing fifos. As far as the svm fifo code is concerned, it's OK to set fifo->nitems anywhere in the interval: [0, 1<<(fifo->freelist_index) + FIFO_SEGMENT_MIN_FIFO_SIZE] It's unlikely that setting nitems below the path MTU will work out very well... Change-Id: Idad73a027dfb7412056cb02988b77e300fa7e8a7 Signed-off-by: Dave Barach <dave@barachs.net>
Diffstat (limited to 'src/svm')
-rw-r--r--src/svm/svm_fifo.c5
-rw-r--r--src/svm/svm_fifo.h3
-rw-r--r--src/svm/svm_fifo_segment.c130
-rw-r--r--src/svm/svm_fifo_segment.h6
4 files changed, 127 insertions, 17 deletions
diff --git a/src/svm/svm_fifo.c b/src/svm/svm_fifo.c
index e478c06e891..7f8127cfa69 100644
--- a/src/svm/svm_fifo.c
+++ b/src/svm/svm_fifo.c
@@ -192,8 +192,11 @@ svm_fifo_t *
svm_fifo_create (u32 data_size_in_bytes)
{
svm_fifo_t *f;
+ u32 rounded_data_size;
- f = clib_mem_alloc_aligned_or_null (sizeof (*f) + data_size_in_bytes,
+ /* always round fifo data size to the next highest power-of-two */
+ rounded_data_size = (1 << (max_log2 (data_size_in_bytes)));
+ f = clib_mem_alloc_aligned_or_null (sizeof (*f) + rounded_data_size,
CLIB_CACHE_LINE_BYTES);
if (f == 0)
return 0;
diff --git a/src/svm/svm_fifo.h b/src/svm/svm_fifo.h
index f10b4d91a2a..84901d022d6 100644
--- a/src/svm/svm_fifo.h
+++ b/src/svm/svm_fifo.h
@@ -75,7 +75,8 @@ typedef struct _svm_fifo
#if SVM_FIFO_TRACE
svm_fifo_trace_elem_t *trace;
#endif
- i8 refcnt;
+ u32 freelist_index; /**< aka log2(allocated_size) - const. */
+ i8 refcnt; /**< reference count */
CLIB_CACHE_LINE_ALIGN_MARK (data);
} svm_fifo_t;
diff --git a/src/svm/svm_fifo_segment.c b/src/svm/svm_fifo_segment.c
index c04b9d8ccba..2094ba74a9f 100644
--- a/src/svm/svm_fifo_segment.c
+++ b/src/svm/svm_fifo_segment.c
@@ -18,12 +18,53 @@
svm_fifo_segment_main_t svm_fifo_segment_main;
static void
+allocate_new_fifo_chunk (svm_fifo_segment_header_t * fsh,
+ u32 data_size_in_bytes, int chunk_size)
+{
+ int freelist_index;
+ u32 size;
+ u8 *fifo_space;
+ u32 rounded_data_size;
+ svm_fifo_t *f;
+ int i;
+
+ rounded_data_size = (1 << (max_log2 (data_size_in_bytes)));
+ freelist_index = max_log2 (rounded_data_size)
+ - max_log2 (FIFO_SEGMENT_MIN_FIFO_SIZE);
+
+ /* Calculate space requirement $$$ round-up data_size_in_bytes */
+ size = (sizeof (*f) + rounded_data_size) * chunk_size;
+
+ /* Allocate fifo space. May fail. */
+ fifo_space = clib_mem_alloc_aligned_at_offset
+ (size, CLIB_CACHE_LINE_BYTES, 0 /* align_offset */ ,
+ 0 /* os_out_of_memory */ );
+
+ /* Out of space.. */
+ if (fifo_space == 0)
+ return;
+
+ /* Carve fifo space */
+ f = (svm_fifo_t *) fifo_space;
+ for (i = 0; i < chunk_size; i++)
+ {
+ f->freelist_index = freelist_index;
+ f->next = fsh->free_fifos[freelist_index];
+ fsh->free_fifos[freelist_index] = f;
+ fifo_space += sizeof (*f) + rounded_data_size;
+ f = (svm_fifo_t *) fifo_space;
+ }
+}
+
+static void
preallocate_fifo_pairs (svm_fifo_segment_header_t * fsh,
svm_fifo_segment_create_args_t * a)
{
u32 rx_fifo_size, tx_fifo_size;
+ u32 rx_rounded_data_size, tx_rounded_data_size;
svm_fifo_t *f;
u8 *rx_fifo_space, *tx_fifo_space;
+ int rx_freelist_index, tx_freelist_index;
int i;
/* Parameter check */
@@ -31,10 +72,39 @@ preallocate_fifo_pairs (svm_fifo_segment_header_t * fsh,
|| a->preallocated_fifo_pairs == 0)
return;
- /* Calculate space requirements */
- rx_fifo_size = (sizeof (*f) + a->rx_fifo_size) * a->preallocated_fifo_pairs;
- tx_fifo_size = (sizeof (*f) + a->tx_fifo_size) * a->preallocated_fifo_pairs;
+ if (a->rx_fifo_size < FIFO_SEGMENT_MIN_FIFO_SIZE ||
+ a->rx_fifo_size > FIFO_SEGMENT_MAX_FIFO_SIZE)
+ {
+ clib_warning ("rx fifo_size out of range %d", a->rx_fifo_size);
+ return;
+ }
+
+ if (a->tx_fifo_size < FIFO_SEGMENT_MIN_FIFO_SIZE ||
+ a->tx_fifo_size > FIFO_SEGMENT_MAX_FIFO_SIZE)
+ {
+ clib_warning ("tx fifo_size out of range %d", a->rx_fifo_size);
+ return;
+ }
+
+ rx_rounded_data_size = (1 << (max_log2 (a->rx_fifo_size)));
+
+ rx_freelist_index = max_log2 (a->rx_fifo_size)
+ - max_log2 (FIFO_SEGMENT_MIN_FIFO_SIZE);
+
+ tx_rounded_data_size = (1 << (max_log2 (a->rx_fifo_size)));
+
+ tx_freelist_index = max_log2 (a->tx_fifo_size)
+ - max_log2 (FIFO_SEGMENT_MIN_FIFO_SIZE);
+ /* Calculate space requirements */
+ rx_fifo_size = (sizeof (*f) + rx_rounded_data_size)
+ * a->preallocated_fifo_pairs;
+ tx_fifo_size = (sizeof (*f) + tx_rounded_data_size)
+ * a->preallocated_fifo_pairs;
+
+ vec_validate_init_empty (fsh->free_fifos,
+ clib_max (rx_freelist_index, tx_freelist_index),
+ 0);
if (0)
clib_warning ("rx_fifo_size %u (%d mb), tx_fifo_size %u (%d mb)",
rx_fifo_size, rx_fifo_size >> 20,
@@ -71,18 +141,20 @@ preallocate_fifo_pairs (svm_fifo_segment_header_t * fsh,
f = (svm_fifo_t *) rx_fifo_space;
for (i = 0; i < a->preallocated_fifo_pairs; i++)
{
- f->next = fsh->free_fifos[FIFO_SEGMENT_RX_FREELIST];
- fsh->free_fifos[FIFO_SEGMENT_RX_FREELIST] = f;
- rx_fifo_space += sizeof (*f) + a->rx_fifo_size;
+ f->freelist_index = rx_freelist_index;
+ f->next = fsh->free_fifos[rx_freelist_index];
+ fsh->free_fifos[rx_freelist_index] = f;
+ rx_fifo_space += sizeof (*f) + rx_rounded_data_size;
f = (svm_fifo_t *) rx_fifo_space;
}
/* Carve tx fifo space */
f = (svm_fifo_t *) tx_fifo_space;
for (i = 0; i < a->preallocated_fifo_pairs; i++)
{
- f->next = fsh->free_fifos[FIFO_SEGMENT_TX_FREELIST];
- fsh->free_fifos[FIFO_SEGMENT_TX_FREELIST] = f;
- tx_fifo_space += sizeof (*f) + a->tx_fifo_size;
+ f->freelist_index = tx_freelist_index;
+ f->next = fsh->free_fifos[tx_freelist_index];
+ fsh->free_fifos[tx_freelist_index] = f;
+ tx_fifo_space += sizeof (*f) + tx_rounded_data_size;
f = (svm_fifo_t *) tx_fifo_space;
}
}
@@ -277,6 +349,21 @@ svm_fifo_segment_alloc_fifo (svm_fifo_segment_private_t * s,
svm_fifo_segment_header_t *fsh;
svm_fifo_t *f;
void *oldheap;
+ int freelist_index;
+
+ /*
+ * 2K minimum. It's not likely that anything good will happen
+ * with a 1K FIFO.
+ */
+ if (data_size_in_bytes < FIFO_SEGMENT_MIN_FIFO_SIZE ||
+ data_size_in_bytes > FIFO_SEGMENT_MAX_FIFO_SIZE)
+ {
+ clib_warning ("fifo size out of range %d", data_size_in_bytes);
+ return 0;
+ }
+
+ freelist_index = max_log2 (data_size_in_bytes)
+ - max_log2 (FIFO_SEGMENT_MIN_FIFO_SIZE);
sh = s->ssvm.sh;
fsh = (svm_fifo_segment_header_t *) sh->opaque[0];
@@ -288,15 +375,24 @@ svm_fifo_segment_alloc_fifo (svm_fifo_segment_private_t * s,
{
case FIFO_SEGMENT_RX_FREELIST:
case FIFO_SEGMENT_TX_FREELIST:
- f = fsh->free_fifos[list_index];
- if (f)
+ vec_validate_init_empty (fsh->free_fifos, freelist_index, 0);
+
+ f = fsh->free_fifos[freelist_index];
+ if (PREDICT_FALSE (f == 0))
{
- fsh->free_fifos[list_index] = f->next;
+ allocate_new_fifo_chunk (fsh, data_size_in_bytes,
+ FIFO_SEGMENT_ALLOC_CHUNK_SIZE);
+ f = fsh->free_fifos[freelist_index];
+ }
+ if (PREDICT_TRUE (f != 0))
+ {
+ fsh->free_fifos[freelist_index] = f->next;
/* (re)initialize the fifo, as in svm_fifo_create */
memset (f, 0, sizeof (*f));
f->nitems = data_size_in_bytes;
f->ooos_list_head = OOO_SEGMENT_INVALID_INDEX;
f->refcnt = 1;
+ f->freelist_index = freelist_index;
goto found;
}
/* FALLTHROUGH */
@@ -316,6 +412,7 @@ svm_fifo_segment_alloc_fifo (svm_fifo_segment_private_t * s,
ssvm_unlock_non_recursive (sh);
return (0);
}
+ f->freelist_index = freelist_index;
found:
/* If rx_freelist add to active fifos list. When cleaning up segment,
@@ -344,6 +441,7 @@ svm_fifo_segment_free_fifo (svm_fifo_segment_private_t * s, svm_fifo_t * f,
ssvm_shared_header_t *sh;
svm_fifo_segment_header_t *fsh;
void *oldheap;
+ int freelist_index;
ASSERT (f->refcnt > 0);
@@ -353,6 +451,10 @@ svm_fifo_segment_free_fifo (svm_fifo_segment_private_t * s, svm_fifo_t * f,
sh = s->ssvm.sh;
fsh = (svm_fifo_segment_header_t *) sh->opaque[0];
+ freelist_index = f->freelist_index;
+
+ ASSERT (freelist_index > 0 && freelist_index < vec_len (fsh->free_fifos));
+
ssvm_lock_non_recursive (sh, 2);
oldheap = ssvm_push_heap (sh);
@@ -369,9 +471,9 @@ svm_fifo_segment_free_fifo (svm_fifo_segment_private_t * s, svm_fifo_t * f,
/* Fall through: we add only rx fifos to active pool */
case FIFO_SEGMENT_TX_FREELIST:
/* Add to free list */
- f->next = fsh->free_fifos[list_index];
+ f->next = fsh->free_fifos[freelist_index];
f->prev = 0;
- fsh->free_fifos[list_index] = f;
+ fsh->free_fifos[freelist_index] = f;
break;
case FIFO_SEGMENT_FREELIST_NONE:
break;
diff --git a/src/svm/svm_fifo_segment.h b/src/svm/svm_fifo_segment.h
index a7a3f469bab..68bb4d3d57d 100644
--- a/src/svm/svm_fifo_segment.h
+++ b/src/svm/svm_fifo_segment.h
@@ -27,11 +27,15 @@ typedef enum
FIFO_SEGMENT_N_FREELISTS
} svm_fifo_segment_freelist_t;
+#define FIFO_SEGMENT_MIN_FIFO_SIZE 2048
+#define FIFO_SEGMENT_MAX_FIFO_SIZE (8<<20) /* 8mb max fifo size */
+#define FIFO_SEGMENT_ALLOC_CHUNK_SIZE 32 /* allocation quantum */
+
typedef struct
{
svm_fifo_t *fifos; /**< Linked list of active RX fifos */
u8 *segment_name; /**< Segment name */
- svm_fifo_t *free_fifos[FIFO_SEGMENT_N_FREELISTS]; /**< Free lists */
+ svm_fifo_t **free_fifos; /**< Freelists, by fifo size */
} svm_fifo_segment_header_t;
typedef struct