diff options
Diffstat (limited to 'src/svm')
| -rw-r--r-- | src/svm/svm_fifo.c | 435 | ||||
| -rw-r--r-- | src/svm/svm_fifo.h | 195 | ||||
| -rw-r--r-- | src/svm/svm_fifo_segment.c | 7 |
3 files changed, 393 insertions, 244 deletions
diff --git a/src/svm/svm_fifo.c b/src/svm/svm_fifo.c index 7aecbb81619..918ad77956e 100644 --- a/src/svm/svm_fifo.c +++ b/src/svm/svm_fifo.c @@ -1,5 +1,9 @@ /* * Copyright (c) 2016-2019 Cisco and/or its affiliates. + * Copyright (c) 2019 Arm Limited + * Copyright (c) 2010-2017 Intel Corporation and/or its affiliates. + * Copyright (c) 2007-2009 Kip Macy kmacy@freebsd.org + * Inspired from DPDK rte_ring.h (SPSC only) (derived from freebsd bufring.h). * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at: @@ -17,37 +21,37 @@ #include <vppinfra/cpu.h> static inline u8 -position_lt (svm_fifo_t * f, u32 a, u32 b) +position_lt (svm_fifo_t * f, u32 a, u32 b, u32 tail) { - return (ooo_segment_distance_from_tail (f, a) - < ooo_segment_distance_from_tail (f, b)); + return (ooo_segment_distance_from_tail (f, a, tail) + < ooo_segment_distance_from_tail (f, b, tail)); } static inline u8 -position_leq (svm_fifo_t * f, u32 a, u32 b) +position_leq (svm_fifo_t * f, u32 a, u32 b, u32 tail) { - return (ooo_segment_distance_from_tail (f, a) - <= ooo_segment_distance_from_tail (f, b)); + return (ooo_segment_distance_from_tail (f, a, tail) + <= ooo_segment_distance_from_tail (f, b, tail)); } static inline u8 -position_gt (svm_fifo_t * f, u32 a, u32 b) +position_gt (svm_fifo_t * f, u32 a, u32 b, u32 tail) { - return (ooo_segment_distance_from_tail (f, a) - > ooo_segment_distance_from_tail (f, b)); + return (ooo_segment_distance_from_tail (f, a, tail) + > ooo_segment_distance_from_tail (f, b, tail)); } static inline u32 -position_diff (svm_fifo_t * f, u32 posa, u32 posb) +position_diff (svm_fifo_t * f, u32 posa, u32 posb, u32 tail) { - return ooo_segment_distance_from_tail (f, posa) - - ooo_segment_distance_from_tail (f, posb); + return ooo_segment_distance_from_tail (f, posa, tail) + - ooo_segment_distance_from_tail (f, posb, tail); } static inline u32 ooo_segment_end_pos (svm_fifo_t * f, ooo_segment_t * s) { - return (s->start + s->length) % f->nitems; + return s->start + s->length; } #ifndef CLIB_MARCH_VARIANT @@ -57,9 +61,9 @@ format_ooo_segment (u8 * s, va_list * args) { svm_fifo_t *f = va_arg (*args, svm_fifo_t *); ooo_segment_t *seg = va_arg (*args, ooo_segment_t *); - u32 normalized_start = (seg->start + f->nitems - f->tail) % f->nitems; + u32 normalized_start = (seg->start + f->nitems - f->tail) % f->size; s = format (s, "[%u, %u], len %u, next %d, prev %d", normalized_start, - (normalized_start + seg->length) % f->nitems, seg->length, + (normalized_start + seg->length) % f->size, seg->length, seg->next, seg->prev); return s; } @@ -108,7 +112,7 @@ svm_fifo_replay (u8 * s, svm_fifo_t * f, u8 no_read, u8 verbose) trace_len = 0; #endif - dummy_fifo = svm_fifo_create (f->nitems); + dummy_fifo = svm_fifo_create (f->size); clib_memset (f->data, 0xFF, f->nitems); vec_validate (data, f->nitems); @@ -122,8 +126,7 @@ svm_fifo_replay (u8 * s, svm_fifo_t * f, u8 no_read, u8 verbose) { if (verbose) s = format (s, "adding [%u, %u]:", trace[i].offset, - (trace[i].offset + - trace[i].len) % dummy_fifo->nitems); + (trace[i].offset + trace[i].len) % dummy_fifo->size); svm_fifo_enqueue_with_offset (dummy_fifo, trace[i].offset, trace[i].len, &data[offset]); } @@ -179,9 +182,10 @@ format_svm_fifo (u8 * s, va_list * args) indent = format_get_indent (s); s = format (s, "cursize %u nitems %u has_event %d\n", - f->cursize, f->nitems, f->has_event); - s = format (s, "%Uhead %d tail %d segment manager %u\n", format_white_space, - indent, f->head, f->tail, f->segment_manager); + svm_fifo_max_dequeue (f), f->nitems, f->has_event); + s = format (s, "%Uhead %u tail %u segment manager %u\n", format_white_space, + indent, (f->head % f->size), (f->tail % f->size), + f->segment_manager); if (verbose > 1) s = format (s, "%Uvpp session %d thread %d app session %d thread %d\n", @@ -215,7 +219,12 @@ svm_fifo_create (u32 data_size_in_bytes) return 0; clib_memset (f, 0, sizeof (*f)); - f->nitems = data_size_in_bytes; + f->size = rounded_data_size; + /* + * usable size of the fifo set to rounded_data_size - 1 + * to differentiate between free fifo and empty fifo. + */ + f->nitems = f->size - 1; f->ooos_list_head = OOO_SEGMENT_INVALID_INDEX; f->ct_session_index = SVM_FIFO_INVALID_SESSION_INDEX; f->segment_index = SVM_FIFO_INVALID_INDEX; @@ -281,21 +290,21 @@ ooo_segment_del (svm_fifo_t * f, u32 index) * adjacent segments and removing overlapping ones. */ static void -ooo_segment_add (svm_fifo_t * f, u32 offset, u32 length) +ooo_segment_add (svm_fifo_t * f, u32 offset, u32 head, u32 tail, u32 length) { ooo_segment_t *s, *new_s, *prev, *next, *it; u32 new_index, s_end_pos, s_index; - u32 normalized_position, normalized_end_position; + u32 offset_pos, offset_end_pos; - ASSERT (offset + length <= ooo_segment_distance_from_tail (f, f->head)); - normalized_position = (f->tail + offset) % f->nitems; - normalized_end_position = (f->tail + offset + length) % f->nitems; + ASSERT (offset + length <= ooo_segment_distance_from_tail (f, head, tail)); + offset_pos = tail + offset; + offset_end_pos = tail + offset + length; f->ooos_newest = OOO_SEGMENT_INVALID_INDEX; if (f->ooos_list_head == OOO_SEGMENT_INVALID_INDEX) { - s = ooo_segment_new (f, normalized_position, length); + s = ooo_segment_new (f, offset_pos, length); f->ooos_list_head = s - f->ooo_segments; f->ooos_newest = f->ooos_list_head; return; @@ -304,20 +313,20 @@ ooo_segment_add (svm_fifo_t * f, u32 offset, u32 length) /* Find first segment that starts after new segment */ s = pool_elt_at_index (f->ooo_segments, f->ooos_list_head); while (s->next != OOO_SEGMENT_INVALID_INDEX - && position_lt (f, s->start, normalized_position)) + && position_lt (f, s->start, offset_pos, tail)) s = pool_elt_at_index (f->ooo_segments, s->next); /* If we have a previous and we overlap it, use it as starting point */ prev = ooo_segment_get_prev (f, s); if (prev - && position_leq (f, normalized_position, ooo_segment_end_pos (f, prev))) + && position_leq (f, offset_pos, ooo_segment_end_pos (f, prev), tail)) { s = prev; s_end_pos = ooo_segment_end_pos (f, s); - /* Since we have previous, normalized start position cannot be smaller + /* Since we have previous, offset start position cannot be smaller * than prev->start. Check tail */ - ASSERT (position_lt (f, s->start, normalized_position)); + ASSERT (position_lt (f, s->start, offset_pos, tail)); goto check_tail; } @@ -325,9 +334,9 @@ ooo_segment_add (svm_fifo_t * f, u32 offset, u32 length) s_end_pos = ooo_segment_end_pos (f, s); /* No overlap, add before current segment */ - if (position_lt (f, normalized_end_position, s->start)) + if (position_lt (f, offset_end_pos, s->start, tail)) { - new_s = ooo_segment_new (f, normalized_position, length); + new_s = ooo_segment_new (f, offset_pos, length); new_index = new_s - f->ooo_segments; /* Pool might've moved, get segment again */ @@ -350,9 +359,9 @@ ooo_segment_add (svm_fifo_t * f, u32 offset, u32 length) return; } /* No overlap, add after current segment */ - else if (position_gt (f, normalized_position, s_end_pos)) + else if (position_gt (f, offset_pos, s_end_pos, tail)) { - new_s = ooo_segment_new (f, normalized_position, length); + new_s = ooo_segment_new (f, offset_pos, length); new_index = new_s - f->ooo_segments; /* Pool might've moved, get segment again */ @@ -373,24 +382,24 @@ ooo_segment_add (svm_fifo_t * f, u32 offset, u32 length) */ /* Merge at head */ - if (position_lt (f, normalized_position, s->start)) + if (position_lt (f, offset_pos, s->start, tail)) { - s->start = normalized_position; - s->length = position_diff (f, s_end_pos, s->start); + s->start = offset_pos; + s->length = position_diff (f, s_end_pos, s->start, tail); f->ooos_newest = s - f->ooo_segments; } check_tail: /* Overlapping tail */ - if (position_gt (f, normalized_end_position, s_end_pos)) + if (position_gt (f, offset_end_pos, s_end_pos, tail)) { - s->length = position_diff (f, normalized_end_position, s->start); + s->length = position_diff (f, offset_end_pos, s->start, tail); /* Remove the completely overlapped segments in the tail */ it = ooo_segment_next (f, s); while (it && position_leq (f, ooo_segment_end_pos (f, it), - normalized_end_position)) + offset_end_pos, tail)) { next = ooo_segment_next (f, it); ooo_segment_del (f, it - f->ooo_segments); @@ -398,10 +407,10 @@ check_tail: } /* If partial overlap with last, merge */ - if (it && position_leq (f, it->start, normalized_end_position)) + if (it && position_leq (f, it->start, offset_end_pos, tail)) { s->length = position_diff (f, ooo_segment_end_pos (f, it), - s->start); + s->start, tail); ooo_segment_del (f, it - f->ooo_segments); } f->ooos_newest = s - f->ooo_segments; @@ -413,14 +422,14 @@ check_tail: * advanced. Returns the number of bytes added to tail. */ static int -ooo_segment_try_collect (svm_fifo_t * f, u32 n_bytes_enqueued) +ooo_segment_try_collect (svm_fifo_t * f, u32 n_bytes_enqueued, u32 * tail) { ooo_segment_t *s; u32 index, bytes = 0; i32 diff; s = pool_elt_at_index (f->ooo_segments, f->ooos_list_head); - diff = ooo_segment_distance_to_tail (f, s->start); + diff = ooo_segment_distance_to_tail (f, s->start, *tail); ASSERT (diff != n_bytes_enqueued); @@ -436,8 +445,7 @@ ooo_segment_try_collect (svm_fifo_t * f, u32 n_bytes_enqueued) if (s->length > diff) { bytes = s->length - diff; - f->tail += bytes; - f->tail %= f->nitems; + *tail = *tail + bytes; ooo_segment_del (f, index); break; } @@ -446,7 +454,7 @@ ooo_segment_try_collect (svm_fifo_t * f, u32 n_bytes_enqueued) if (s->next != OOO_SEGMENT_INVALID_INDEX) { s = pool_elt_at_index (f->ooo_segments, s->next); - diff = ooo_segment_distance_to_tail (f, s->start); + diff = ooo_segment_distance_to_tail (f, s->start, *tail); ooo_segment_del (f, index); } /* End of search */ @@ -465,64 +473,63 @@ CLIB_MARCH_FN (svm_fifo_enqueue_nowait, int, svm_fifo_t * f, u32 max_bytes, const u8 * copy_from_here) { u32 total_copy_bytes, first_copy_bytes, second_copy_bytes; - u32 cursize, nitems; + u32 tail, head, free_count, tail_idx; + + f_load_head_tail_prod (f, &head, &tail); + + /* free space in fifo can only increase during enqueue: SPSC */ + free_count = f_free_count (f, head, tail); - /* read cursize, which can only increase while we're working */ - cursize = svm_fifo_max_dequeue (f); f->ooos_newest = OOO_SEGMENT_INVALID_INDEX; - if (PREDICT_FALSE (cursize == f->nitems)) + if (PREDICT_FALSE (free_count == 0)) return SVM_FIFO_FULL; - nitems = f->nitems; + /* number of bytes we're going to copy */ + total_copy_bytes = free_count < max_bytes ? free_count : max_bytes; - /* Number of bytes we're going to copy */ - total_copy_bytes = (nitems - cursize) < max_bytes ? - (nitems - cursize) : max_bytes; + tail_idx = tail % f->size; if (PREDICT_TRUE (copy_from_here != 0)) { - /* Number of bytes in first copy segment */ - first_copy_bytes = ((nitems - f->tail) < total_copy_bytes) - ? (nitems - f->tail) : total_copy_bytes; - - clib_memcpy_fast (&f->data[f->tail], copy_from_here, first_copy_bytes); - f->tail += first_copy_bytes; - f->tail = (f->tail == nitems) ? 0 : f->tail; - - /* Number of bytes in second copy segment, if any */ - second_copy_bytes = total_copy_bytes - first_copy_bytes; - if (second_copy_bytes) + first_copy_bytes = f->size - tail_idx; + if (first_copy_bytes < total_copy_bytes) { - clib_memcpy_fast (&f->data[f->tail], + clib_memcpy_fast (&f->data[tail_idx], copy_from_here, + first_copy_bytes); + /* number of bytes in second copy segment */ + second_copy_bytes = total_copy_bytes - first_copy_bytes; + /* wrap around */ + clib_memcpy_fast (&f->data[0], copy_from_here + first_copy_bytes, second_copy_bytes); - f->tail += second_copy_bytes; - f->tail = (f->tail == nitems) ? 0 : f->tail; } + else + { + clib_memcpy_fast (&f->data[tail_idx], copy_from_here, + total_copy_bytes); + } + tail += total_copy_bytes; } else { ASSERT (0); - /* Account for a zero-copy enqueue done elsewhere */ - ASSERT (max_bytes <= (nitems - cursize)); - f->tail += max_bytes; - f->tail = f->tail % nitems; - total_copy_bytes = max_bytes; + tail += max_bytes; } - svm_fifo_trace_add (f, f->head, total_copy_bytes, 2); + svm_fifo_trace_add (f, head, total_copy_bytes, 2); - /* Any out-of-order segments to collect? */ + /* collect out-of-order segments */ if (PREDICT_FALSE (f->ooos_list_head != OOO_SEGMENT_INVALID_INDEX)) - total_copy_bytes += ooo_segment_try_collect (f, total_copy_bytes); + total_copy_bytes += ooo_segment_try_collect (f, total_copy_bytes, &tail); - /* Atomically increase the queue length */ - ASSERT (cursize + total_copy_bytes <= nitems); - clib_atomic_fetch_add_rel (&f->cursize, total_copy_bytes); + ASSERT (total_copy_bytes <= free_count); - return (total_copy_bytes); + /* store-rel: producer owned index (paired with load-acq in consumer) */ + clib_atomic_store_rel_n (&f->tail, tail); + + return total_copy_bytes; } #ifndef CLIB_MARCH_VARIANT @@ -546,50 +553,53 @@ CLIB_MARCH_FN (svm_fifo_enqueue_with_offset, int, svm_fifo_t * f, u32 offset, u32 required_bytes, u8 * copy_from_here) { u32 total_copy_bytes, first_copy_bytes, second_copy_bytes; - u32 cursize, nitems, normalized_offset; + u32 tail_offset; + u32 tail, head, free_count, tail_offset_idx; - f->ooos_newest = OOO_SEGMENT_INVALID_INDEX; + f_load_head_tail_prod (f, &head, &tail); - /* read cursize, which can only increase while we're working */ - cursize = svm_fifo_max_dequeue (f); - nitems = f->nitems; + /* free space in fifo can only increase during enqueue: SPSC */ + free_count = f_free_count (f, head, tail); - ASSERT (required_bytes < nitems); + /* will this request fit? */ + if ((required_bytes + offset) > free_count) + return -1; - normalized_offset = (f->tail + offset) % nitems; + f->ooos_newest = OOO_SEGMENT_INVALID_INDEX; - /* Will this request fit? */ - if ((required_bytes + offset) > (nitems - cursize)) - return -1; + ASSERT (required_bytes < f->nitems); + + tail_offset = tail + offset; + tail_offset_idx = tail_offset % f->size; svm_fifo_trace_add (f, offset, required_bytes, 1); - ooo_segment_add (f, offset, required_bytes); + ooo_segment_add (f, offset, head, tail, required_bytes); - /* Number of bytes we're going to copy */ + /* number of bytes we're going to copy */ total_copy_bytes = required_bytes; - /* Number of bytes in first copy segment */ - first_copy_bytes = ((nitems - normalized_offset) < total_copy_bytes) - ? (nitems - normalized_offset) : total_copy_bytes; - - clib_memcpy_fast (&f->data[normalized_offset], copy_from_here, - first_copy_bytes); + /* number of bytes in first copy segment */ + first_copy_bytes = f->size - tail_offset_idx; - /* Number of bytes in second copy segment, if any */ - second_copy_bytes = total_copy_bytes - first_copy_bytes; - if (second_copy_bytes) + if (first_copy_bytes < total_copy_bytes) { - normalized_offset += first_copy_bytes; - normalized_offset %= nitems; + clib_memcpy_fast (&f->data[tail_offset_idx], copy_from_here, + first_copy_bytes); - ASSERT (normalized_offset == 0); - - clib_memcpy_fast (&f->data[normalized_offset], + /* number of bytes in second copy segment */ + second_copy_bytes = total_copy_bytes - first_copy_bytes; + /* wrap around */ + clib_memcpy_fast (&f->data[0], copy_from_here + first_copy_bytes, second_copy_bytes); } + else + { + clib_memcpy_fast (&f->data[tail_offset_idx], copy_from_here, + total_copy_bytes); + } - return (0); + return 0; } #ifndef CLIB_MARCH_VARIANT @@ -607,13 +617,17 @@ void svm_fifo_overwrite_head (svm_fifo_t * f, u8 * data, u32 len) { u32 first_chunk; - first_chunk = f->nitems - f->head; + u32 head, tail, head_idx; + + f_load_head_tail_cons (f, &head, &tail); + head_idx = head % f->size; + first_chunk = f->size - (head_idx); ASSERT (len <= f->nitems); if (len <= first_chunk) - clib_memcpy_fast (&f->data[f->head], data, len); + clib_memcpy_fast (&f->data[head_idx], data, len); else { - clib_memcpy_fast (&f->data[f->head], data, first_chunk); + clib_memcpy_fast (&f->data[head_idx], data, first_chunk); clib_memcpy_fast (&f->data[0], data + first_chunk, len - first_chunk); } } @@ -623,53 +637,52 @@ CLIB_MARCH_FN (svm_fifo_dequeue_nowait, int, svm_fifo_t * f, u32 max_bytes, u8 * copy_here) { u32 total_copy_bytes, first_copy_bytes, second_copy_bytes; - u32 cursize, nitems; + u32 tail, head, cursize, head_idx; + + f_load_head_tail_cons (f, &head, &tail); + + /* current size of fifo can only increase during dequeue: SPSC */ + cursize = f_cursize (f, head, tail); - /* read cursize, which can only increase while we're working */ - cursize = svm_fifo_max_dequeue (f); if (PREDICT_FALSE (cursize == 0)) return -2; /* nothing in the fifo */ - nitems = f->nitems; - - /* Number of bytes we're going to copy */ + /* number of bytes we're going to copy */ total_copy_bytes = (cursize < max_bytes) ? cursize : max_bytes; + head_idx = head % f->size; + if (PREDICT_TRUE (copy_here != 0)) { - /* Number of bytes in first copy segment */ - first_copy_bytes = ((nitems - f->head) < total_copy_bytes) - ? (nitems - f->head) : total_copy_bytes; - clib_memcpy_fast (copy_here, &f->data[f->head], first_copy_bytes); - f->head += first_copy_bytes; - f->head = (f->head == nitems) ? 0 : f->head; - - /* Number of bytes in second copy segment, if any */ - second_copy_bytes = total_copy_bytes - first_copy_bytes; - if (second_copy_bytes) + /* number of bytes in first copy segment */ + first_copy_bytes = f->size - head_idx; + if (first_copy_bytes < total_copy_bytes) { + clib_memcpy_fast (copy_here, &f->data[head_idx], first_copy_bytes); + /* number of bytes in second copy segment */ + second_copy_bytes = total_copy_bytes - first_copy_bytes; + /* wrap around */ clib_memcpy_fast (copy_here + first_copy_bytes, - &f->data[f->head], second_copy_bytes); - f->head += second_copy_bytes; - f->head = (f->head == nitems) ? 0 : f->head; + &f->data[0], second_copy_bytes); + } + else + { + clib_memcpy_fast (copy_here, &f->data[head_idx], total_copy_bytes); } + head += total_copy_bytes; } else { ASSERT (0); /* Account for a zero-copy dequeue done elsewhere */ - ASSERT (max_bytes <= cursize); - f->head += max_bytes; - f->head = f->head % nitems; - cursize -= max_bytes; - total_copy_bytes = max_bytes; + head += max_bytes; } - ASSERT (f->head <= nitems); ASSERT (cursize >= total_copy_bytes); - clib_atomic_fetch_sub_rel (&f->cursize, total_copy_bytes); + /* store-rel: consumer owned index (paired with load-acq in producer) */ + clib_atomic_store_rel_n (&f->head, head); - return (total_copy_bytes); + return total_copy_bytes; } #ifndef CLIB_MARCH_VARIANT @@ -686,36 +699,42 @@ CLIB_MARCH_FN (svm_fifo_peek, int, svm_fifo_t * f, u32 relative_offset, u32 max_bytes, u8 * copy_here) { u32 total_copy_bytes, first_copy_bytes, second_copy_bytes; - u32 cursize, nitems, real_head; + u32 tail, head, cursize; + u32 relative_head_idx; + + f_load_head_tail_cons (f, &head, &tail); + + /* current size of fifo can only increase during peek: SPSC */ + cursize = f_cursize (f, head, tail); - /* read cursize, which can only increase while we're working */ - cursize = svm_fifo_max_dequeue (f); if (PREDICT_FALSE (cursize < relative_offset)) return -2; /* nothing in the fifo */ - nitems = f->nitems; - real_head = f->head + relative_offset; - real_head = real_head >= nitems ? real_head - nitems : real_head; + relative_head_idx = (head + relative_offset) % f->size; - /* Number of bytes we're going to copy */ - total_copy_bytes = (cursize - relative_offset < max_bytes) ? + /* number of bytes we're going to copy */ + total_copy_bytes = ((cursize - relative_offset) < max_bytes) ? cursize - relative_offset : max_bytes; if (PREDICT_TRUE (copy_here != 0)) { - /* Number of bytes in first copy segment */ - first_copy_bytes = - ((nitems - real_head) < total_copy_bytes) ? - (nitems - real_head) : total_copy_bytes; - clib_memcpy_fast (copy_here, &f->data[real_head], first_copy_bytes); - - /* Number of bytes in second copy segment, if any */ - second_copy_bytes = total_copy_bytes - first_copy_bytes; - if (second_copy_bytes) + /* number of bytes in first copy segment */ + first_copy_bytes = f->size - relative_head_idx; + if (first_copy_bytes < total_copy_bytes) { + clib_memcpy_fast (copy_here, &f->data[relative_head_idx], + first_copy_bytes); + + /* number of bytes in second copy segment */ + second_copy_bytes = total_copy_bytes - first_copy_bytes; clib_memcpy_fast (copy_here + first_copy_bytes, &f->data[0], second_copy_bytes); } + else + { + clib_memcpy_fast (copy_here, &f->data[relative_head_idx], + total_copy_bytes); + } } return total_copy_bytes; } @@ -733,39 +752,28 @@ svm_fifo_peek (svm_fifo_t * f, u32 relative_offset, u32 max_bytes, int svm_fifo_dequeue_drop (svm_fifo_t * f, u32 max_bytes) { - u32 total_drop_bytes, first_drop_bytes, second_drop_bytes; - u32 cursize, nitems; + u32 total_drop_bytes; + u32 tail, head, cursize; + + f_load_head_tail_cons (f, &head, &tail); + + /* number of bytes we're going to drop */ + cursize = f_cursize (f, head, tail); - /* read cursize, which can only increase while we're working */ - cursize = svm_fifo_max_dequeue (f); if (PREDICT_FALSE (cursize == 0)) return -2; /* nothing in the fifo */ - nitems = f->nitems; + svm_fifo_trace_add (f, tail, total_drop_bytes, 3); - /* Number of bytes we're going to drop */ + /* number of bytes we're going to drop */ total_drop_bytes = (cursize < max_bytes) ? cursize : max_bytes; - svm_fifo_trace_add (f, f->tail, total_drop_bytes, 3); - - /* Number of bytes in first copy segment */ - first_drop_bytes = - ((nitems - f->head) < total_drop_bytes) ? - (nitems - f->head) : total_drop_bytes; - f->head += first_drop_bytes; - f->head = (f->head == nitems) ? 0 : f->head; - - /* Number of bytes in second drop segment, if any */ - second_drop_bytes = total_drop_bytes - first_drop_bytes; - if (second_drop_bytes) - { - f->head += second_drop_bytes; - f->head = (f->head == nitems) ? 0 : f->head; - } + /* move head */ + head += total_drop_bytes; - ASSERT (f->head <= nitems); ASSERT (cursize >= total_drop_bytes); - clib_atomic_fetch_sub_rel (&f->cursize, total_drop_bytes); + /* store-rel: consumer owned index (paired with load-acq in producer) */ + clib_atomic_store_rel_n (&f->head, head); return total_drop_bytes; } @@ -773,32 +781,38 @@ svm_fifo_dequeue_drop (svm_fifo_t * f, u32 max_bytes) void svm_fifo_dequeue_drop_all (svm_fifo_t * f) { - f->head = f->tail; - clib_atomic_fetch_sub_rel (&f->cursize, f->cursize); + /* consumer foreign index */ + u32 tail = clib_atomic_load_acq_n (&f->tail); + /* store-rel: consumer owned index (paired with load-acq in producer) */ + clib_atomic_store_rel_n (&f->head, tail); } int svm_fifo_segments (svm_fifo_t * f, svm_fifo_segment_t * fs) { - u32 cursize, nitems; + u32 cursize, head, tail, head_idx; - /* read cursize, which can only increase while we're working */ - cursize = svm_fifo_max_dequeue (f); - if (PREDICT_FALSE (cursize == 0)) - return -2; + f_load_head_tail_cons (f, &head, &tail); + + /* consumer function, cursize can only increase while we're working */ + cursize = f_cursize (f, head, tail); - nitems = f->nitems; + if (PREDICT_FALSE (cursize == 0)) + return -2; /* nothing in the fifo */ - fs[0].len = ((nitems - f->head) < cursize) ? (nitems - f->head) : cursize; - fs[0].data = f->data + f->head; + head_idx = head % f->size; - if (fs[0].len < cursize) + if (tail < head) { + fs[0].len = f->size - head_idx; + fs[0].data = f->data + head_idx; fs[1].len = cursize - fs[0].len; fs[1].data = f->data; } else { + fs[0].len = cursize; + fs[0].data = f->data + head_idx; fs[1].len = 0; fs[1].data = 0; } @@ -808,20 +822,28 @@ svm_fifo_segments (svm_fifo_t * f, svm_fifo_segment_t * fs) void svm_fifo_segments_free (svm_fifo_t * f, svm_fifo_segment_t * fs) { - u32 total_drop_bytes; + u32 head, head_idx; - ASSERT (fs[0].data == f->data + f->head); - if (fs[1].len) - { - f->head = fs[1].len; - total_drop_bytes = fs[0].len + fs[1].len; - } - else - { - f->head = (f->head + fs[0].len) % f->nitems; - total_drop_bytes = fs[0].len; - } - clib_atomic_fetch_sub_rel (&f->cursize, total_drop_bytes); + /* consumer owned index */ + head = f->head; + head_idx = head % f->size; + + ASSERT (fs[0].data == f->data + head_idx); + head += fs[0].len + fs[1].len; + /* store-rel: consumer owned index (paired with load-acq in producer) */ + clib_atomic_store_rel_n (&f->head, head); +} + +/* Assumption: no prod and cons are accessing either dest or src fifo */ +void +svm_fifo_clone (svm_fifo_t * df, svm_fifo_t * sf) +{ + u32 head, tail; + clib_memcpy_fast (df->data, sf->data, sf->size); + + f_load_head_tail_all_acq (sf, &head, &tail); + clib_atomic_store_rel_n (&df->head, head); + clib_atomic_store_rel_n (&df->tail, tail); } u32 @@ -842,7 +864,8 @@ svm_fifo_first_ooo_segment (svm_fifo_t * f) void svm_fifo_init_pointers (svm_fifo_t * f, u32 pointer) { - f->head = f->tail = pointer % f->nitems; + clib_atomic_store_rel_n (&f->head, pointer); + clib_atomic_store_rel_n (&f->tail, pointer); } void diff --git a/src/svm/svm_fifo.h b/src/svm/svm_fifo.h index 4a119341d8b..94a05938d26 100644 --- a/src/svm/svm_fifo.h +++ b/src/svm/svm_fifo.h @@ -1,5 +1,9 @@ /* * Copyright (c) 2016-2019 Cisco and/or its affiliates. + * Copyright (c) 2019 Arm Limited + * Copyright (c) 2010-2017 Intel Corporation and/or its affiliates. + * Copyright (c) 2007-2009 Kip Macy kmacy@freebsd.org + * Inspired from DPDK rte_ring.h (SPSC only) (derived from freebsd bufring.h). * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at: @@ -59,8 +63,8 @@ typedef struct typedef struct _svm_fifo { CLIB_CACHE_LINE_ALIGN_MARK (shared_first); - volatile u32 cursize; /**< current fifo size */ - u32 nitems; + u32 size; /**< size of the fifo(must be power of 2) */ + u32 nitems; /**< usable size(size-1) */ CLIB_CACHE_LINE_ALIGN_MARK (shared_second); volatile u32 has_event; /**< non-zero if deq event exists */ @@ -125,28 +129,141 @@ typedef struct svm_fifo_segment_ u8 *svm_fifo_dump_trace (u8 * s, svm_fifo_t * f); u8 *svm_fifo_replay (u8 * s, svm_fifo_t * f, u8 no_read, u8 verbose); +/* internal function */ +static inline void +f_load_head_tail_cons (svm_fifo_t * f, u32 * head, u32 * tail) +{ + /* load-relaxed: consumer owned index */ + *head = f->head; + /* load-acq: consumer foreign index (paired with store-rel in producer) */ + *tail = clib_atomic_load_acq_n (&f->tail); +} + +/* internal function */ +static inline void +f_load_head_tail_prod (svm_fifo_t * f, u32 * head, u32 * tail) +{ + /* load relaxed: producer owned index */ + *tail = f->tail; + /* load-acq: producer foreign index (paired with store-rel in consumer) */ + *head = clib_atomic_load_acq_n (&f->head); +} + +/* producer consumer role independent */ +/* internal function */ +static inline void +f_load_head_tail_all_acq (svm_fifo_t * f, u32 * head, u32 * tail) +{ + /* load-acq : consumer foreign index (paired with store-rel) */ + *tail = clib_atomic_load_acq_n (&f->tail); + /* load-acq : producer foriegn index (paired with store-rel) */ + *head = clib_atomic_load_acq_n (&f->head); +} + +/* internal function */ +static inline u32 +f_free_count (svm_fifo_t * f, u32 head, u32 tail) +{ + return (f->nitems + head - tail); +} + +/* internal function */ +static inline u32 +f_cursize (svm_fifo_t * f, u32 head, u32 tail) +{ + return (f->nitems - f_free_count (f, head, tail)); +} + +/* used by consumer */ +static inline u32 +svm_fifo_max_dequeue_cons (svm_fifo_t * f) +{ + u32 tail, head; + f_load_head_tail_cons (f, &head, &tail); + return f_cursize (f, head, tail); +} + +/* used by producer*/ +static inline u32 +svm_fifo_max_dequeue_prod (svm_fifo_t * f) +{ + u32 tail, head; + f_load_head_tail_prod (f, &head, &tail); + return f_cursize (f, head, tail); +} + +/* use producer or consumer specific functions for perfomance. + * svm_fifo_max_dequeue_cons (svm_fifo_t *f) + * svm_fifo_max_dequeue_prod (svm_fifo_t *f) + */ static inline u32 svm_fifo_max_dequeue (svm_fifo_t * f) { - return clib_atomic_load_acq_n (&f->cursize); + u32 tail, head; + f_load_head_tail_all_acq (f, &head, &tail); + return f_cursize (f, head, tail); } +/* used by producer */ +static inline int +svm_fifo_is_full_prod (svm_fifo_t * f) +{ + return (svm_fifo_max_dequeue_prod (f) == f->nitems); +} + +/* use producer or consumer specific functions for perfomance. + * svm_fifo_is_full_prod (svm_fifo_t * f) + * add cons version if needed + */ static inline int svm_fifo_is_full (svm_fifo_t * f) { - return (clib_atomic_load_acq_n (&f->cursize) == f->nitems); + return (svm_fifo_max_dequeue (f) == f->nitems); +} + +/* used by consumer */ +static inline int +svm_fifo_is_empty_cons (svm_fifo_t * f) +{ + return (svm_fifo_max_dequeue_cons (f) == 0); } +/* used by producer */ +static inline int +svm_fifo_is_empty_prod (svm_fifo_t * f) +{ + return (svm_fifo_max_dequeue_prod (f) == 0); +} + +/* use producer or consumer specific functions for perfomance. + * svm_fifo_is_empty_cons (svm_fifo_t * f) + * svm_fifo_is_empty_prod (svm_fifo_t * f) + */ static inline int svm_fifo_is_empty (svm_fifo_t * f) { - return (clib_atomic_load_acq_n (&f->cursize) == 0); + return (svm_fifo_max_dequeue (f) == 0); } +/* used by producer*/ +static inline u32 +svm_fifo_max_enqueue_prod (svm_fifo_t * f) +{ + u32 head, tail; + f_load_head_tail_prod (f, &head, &tail); + return f_free_count (f, head, tail); +} + +/* use producer or consumer specfic functions for perfomance. + * svm_fifo_max_enqueue_prod (svm_fifo_t *f) + * add consumer specific version if needed. + */ static inline u32 svm_fifo_max_enqueue (svm_fifo_t * f) { - return f->nitems - svm_fifo_max_dequeue (f); + u32 head, tail; + f_load_head_tail_all_acq (f, &head, &tail); + return f_free_count (f, head, tail); } static inline int @@ -164,7 +281,7 @@ svm_fifo_has_ooo_data (svm_fifo_t * f) /** * Sets fifo event flag. * - * Also acts as a release barrier. + * Also acts as a release ordering. * * @return 1 if flag was not set. */ @@ -202,6 +319,7 @@ void svm_fifo_dequeue_drop_all (svm_fifo_t * f); int svm_fifo_segments (svm_fifo_t * f, svm_fifo_segment_t * fs); void svm_fifo_segments_free (svm_fifo_t * f, svm_fifo_segment_t * fs); void svm_fifo_init_pointers (svm_fifo_t * f, u32 pointer); +void svm_fifo_clone (svm_fifo_t * df, svm_fifo_t * sf); void svm_fifo_overwrite_head (svm_fifo_t * f, u8 * data, u32 len); void svm_fifo_add_subscriber (svm_fifo_t * f, u8 subscriber); void svm_fifo_del_subscriber (svm_fifo_t * f, u8 subscriber); @@ -213,7 +331,12 @@ format_function_t format_svm_fifo; always_inline u32 svm_fifo_max_read_chunk (svm_fifo_t * f) { - return ((f->tail > f->head) ? (f->tail - f->head) : (f->nitems - f->head)); + u32 head, tail; + u32 head_idx, tail_idx; + f_load_head_tail_cons (f, &head, &tail); + head_idx = head % f->size; + tail_idx = tail % f->size; + return tail_idx > head_idx ? (tail_idx - head_idx) : (f->size - head_idx); } /** @@ -222,7 +345,12 @@ svm_fifo_max_read_chunk (svm_fifo_t * f) always_inline u32 svm_fifo_max_write_chunk (svm_fifo_t * f) { - return ((f->tail >= f->head) ? (f->nitems - f->tail) : (f->head - f->tail)); + u32 head, tail; + u32 head_idx, tail_idx; + f_load_head_tail_prod (f, &head, &tail); + head_idx = head % f->size; + tail_idx = tail % f->size; + return tail_idx >= head_idx ? (f->size - tail_idx) : (head_idx - tail_idx); } /** @@ -233,27 +361,26 @@ svm_fifo_max_write_chunk (svm_fifo_t * f) always_inline void svm_fifo_enqueue_nocopy (svm_fifo_t * f, u32 bytes) { - ASSERT (bytes <= svm_fifo_max_enqueue (f)); - f->tail = (f->tail + bytes) % f->nitems; - clib_atomic_fetch_add_rel (&f->cursize, bytes); + ASSERT (bytes <= svm_fifo_max_enqueue_prod (f)); + /* load-relaxed: producer owned index */ + u32 tail = f->tail; + tail += bytes; + /* store-rel: producer owned index (paired with load-acq in consumer) */ + clib_atomic_store_rel_n (&f->tail, tail); } always_inline u8 * svm_fifo_head (svm_fifo_t * f) { - return (f->data + f->head); + /* load-relaxed: consumer owned index */ + return (f->data + (f->head % f->size)); } always_inline u8 * svm_fifo_tail (svm_fifo_t * f) { - return (f->data + f->tail); -} - -always_inline u32 -svm_fifo_nitems (svm_fifo_t * f) -{ - return f->nitems; + /* load-relaxed: producer owned index */ + return (f->data + (f->tail % f->size)); } static inline void @@ -293,8 +420,8 @@ svm_fifo_needs_tx_ntf (svm_fifo_t * f, u32 n_last_deq) return 1; else if (want_ntf & SVM_FIFO_WANT_TX_NOTIF_IF_FULL) { - u32 max_deq = svm_fifo_max_dequeue (f); - u32 nitems = svm_fifo_nitems (f); + u32 max_deq = svm_fifo_max_dequeue_cons (f); + u32 nitems = f->nitems; if (!f->has_tx_ntf && max_deq < nitems && max_deq + n_last_deq >= nitems) return 1; @@ -328,31 +455,25 @@ svm_fifo_newest_ooo_segment_reset (svm_fifo_t * f) } always_inline u32 -ooo_segment_distance_from_tail (svm_fifo_t * f, u32 pos) +ooo_segment_distance_from_tail (svm_fifo_t * f, u32 pos, u32 tail) { - /* Ambiguous. Assumption is that ooo segments don't touch tail */ - if (PREDICT_FALSE (pos == f->tail && f->tail == f->head)) - return f->nitems; - - return (((f->nitems + pos) - f->tail) % f->nitems); + return ((pos - tail) % f->size); } always_inline u32 -ooo_segment_distance_to_tail (svm_fifo_t * f, u32 pos) +ooo_segment_distance_to_tail (svm_fifo_t * f, u32 pos, u32 tail) { - return (((f->nitems + f->tail) - pos) % f->nitems); + return ((tail - pos) % f->size); } always_inline u32 -ooo_segment_offset (svm_fifo_t * f, ooo_segment_t * s) +ooo_segment_offset_prod (svm_fifo_t * f, ooo_segment_t * s) { - return ooo_segment_distance_from_tail (f, s->start); -} + u32 tail; + /* load-relaxed: producer owned index */ + tail = f->tail; -always_inline u32 -ooo_segment_end_offset (svm_fifo_t * f, ooo_segment_t * s) -{ - return ooo_segment_distance_from_tail (f, s->start) + s->length; + return ooo_segment_distance_from_tail (f, s->start, tail); } always_inline u32 diff --git a/src/svm/svm_fifo_segment.c b/src/svm/svm_fifo_segment.c index e377160f6d8..94bf6a5e73e 100644 --- a/src/svm/svm_fifo_segment.c +++ b/src/svm/svm_fifo_segment.c @@ -381,7 +381,12 @@ svm_fifo_segment_alloc_fifo (svm_fifo_segment_private_t * fs, fsh->free_fifos[freelist_index] = f->next; /* (re)initialize the fifo, as in svm_fifo_create */ clib_memset (f, 0, sizeof (*f)); - f->nitems = data_size_in_bytes; + f->size = (1 << (max_log2 (data_size_in_bytes))); + /* + * usable size of the fifo set to rounded_data_size - 1 + * to differentiate between free fifo and empty fifo. + */ + f->nitems = f->size - 1; f->ooos_list_head = OOO_SEGMENT_INVALID_INDEX; f->ct_session_index = SVM_FIFO_INVALID_SESSION_INDEX; f->refcnt = 1; |