/* -*- Mode: C; c-basic-offset:4 ; indent-tabs-mode:nil -*- */
/*
* Copyright (c) 2011-2015 Los Alamos National Security, LLC. All rights
* reserved.
* $COPYRIGHT$
*
* Additional copyrights may follow
*
* $HEADER$
*/
#if !defined(MCA_BTL_VADER_FBOX_H)
#define MCA_BTL_VADER_FBOX_H
#include "btl_vader.h"
#define MCA_BTL_VADER_POLL_COUNT 31
typedef union mca_btl_vader_fbox_hdr_t {
struct {
/* NTH: on 32-bit platforms loading/unloading the header may be completed
* in multiple instructions. To ensure that seq is never loaded before tag
* and the tag is never read before seq put them in the same 32-bits of the
* header. */
/** message tag */
uint16_t tag;
/** sequence number */
uint16_t seq;
/** message size */
uint32_t size;
} data;
uint64_t ival;
} mca_btl_vader_fbox_hdr_t;
#define MCA_BTL_VADER_FBOX_HDR(x) ((mca_btl_vader_fbox_hdr_t *) (x))
#define MCA_BTL_VADER_FBOX_OFFSET_MASK 0x7fffffff
#define MCA_BTL_VADER_FBOX_HB_MASK 0x80000000
/* if the two offsets are equal and the high bit matches the buffer is empty else the buffer is full.
* note that start will never be end - 1 so this simplified conditional will always produce the correct
* result */
#define BUFFER_FREE(s,e,hbm,size) (((s + !hbm) > (e)) ? (s) - (e) : (size - (e)))
/** macro for checking if the high bit is set */
#define MCA_BTL_VADER_FBOX_OFFSET_HBS(v) (!!((v) & MCA_BTL_VADER_FBOX_HB_MASK))
void mca_btl_vader_poll_handle_frag (mca_btl_vader_hdr_t *hdr, mca_btl_base_endpoint_t *ep);
static inline void mca_btl_vader_fbox_set_header (mca_btl_vader_fbox_hdr_t *hdr, uint16_t tag,
uint16_t seq, uint32_t size)
{
mca_btl_vader_fbox_hdr_t tmp = {.data = {.tag = tag, .seq = seq, .size = size}};
hdr->ival = tmp.ival;
}
/* attempt to reserve a contiguous segment from the remote ep */
static inline unsigned char *mca_btl_vader_reserve_fbox (mca_btl_base_endpoint_t *ep, size_t size)
{
const unsigned int fbox_size = mca_btl_vader_component.fbox_size;
unsigned int start, end, buffer_free;
size_t data_size = size;
unsigned char *dst;
bool hbs, hbm;
/* don't try to use the per-peer buffer for messages that will fill up more than 25% of the buffer */
if (OPAL_UNLIKELY(NULL == ep->fbox_out.buffer || size > (fbox_size >> 2))) {
return NULL;
}
OPAL_THREAD_LOCK(&ep->lock);
/* the high bit helps determine if the buffer is empty or full */
hbs = MCA_BTL_VADER_FBOX_OFFSET_HBS(ep->fbox_out.end);
hbm = MCA_BTL_VADER_FBOX_OFFSET_HBS(ep->fbox_out.start) == hbs;
/* read current start and end offsets and check for free space */
start = ep->fbox_out.start & MCA_BTL_VADER_FBOX_OFFSET_MASK;
end = ep->fbox_out.end & MCA_BTL_VADER_FBOX_OFFSET_MASK;
buffer_free = BUFFER_FREE(start, end, hbm, fbox_size);
/* need space for the fragment + the header */
size = (size + sizeof (mca_btl_vader_fbox_hdr_t) + MCA_BTL_VADER_FBOX_ALIGNMENT_MASK) & ~MCA_BTL_VADER_FBOX_ALIGNMENT_MASK;
dst = ep->fbox_out.buffer + end;
if (OPAL_UNLIKELY(buffer_free < size)) {
/* check if we need to free up space for this fragment */
BTL_VERBOSE(("not enough room for a fragment of size %u. in use buffer segment: {start: %x, end: %x, high bit matches: %d}",
(unsigned) size, start, end, (int) hbm));
/* read the current start pointer from the remote peer and recalculate the available buffer space */
start = ep->fbox_out.start = ep->fbox_out.startp[0];
/* recalculate how much buffer space is available */
start &= MCA_BTL_VADER_FBOX_OFFSET_MASK;
hbm = MCA_BTL_VADER_FBOX_OFFSET_HBS(ep->fbox_out.start) == hbs;
buffer_free = BUFFER_FREE(start, end, hbm, fbox_size);
opal_atomic_rmb ();
/* if this is the end of the buffer and the fragment doesn't fit then mark the remaining buffer space to
* be skipped and check if the fragment can be written at the beginning of the buffer. */
if (OPAL_UNLIKELY(buffer_free > 0 && buffer_free < size && start <= end)) {
BTL_VERBOSE(("message will not fit in remaining buffer space. skipping to beginning"));
mca_btl_vader_fbox_set_header (MCA_BTL_VADER_FBOX_HDR(dst), 0xff, ep->fbox_out.seq++,
buffer_free - sizeof (mca_btl_vader_fbox_hdr_t));
end = MCA_BTL_VADER_FBOX_ALIGNMENT;
/* toggle the high bit */
hbs = !hbs;
/* toggle the high bit match */
buffer_free = BUFFER_FREE(start, end, !hbm, fbox_size);
dst = ep->fbox_out.buffer + end;
}
if (OPAL_UNLIKELY(buffer_free < size)) {
ep->fbox_out.end = (hbs << 31) | end;
opal_atomic_wmb ();
OPAL_THREAD_UNLOCK(&ep->lock);
return NULL;
}
}
BTL_VERBOSE(("writing fragment of size %u to offset %u {start: 0x%x, end: 0x%x (hbs: %d)} of peer's buffer. free = %u",
(unsigned int) size, end, start, end, hbs, buffer_free));
/* write out part of the header now. the tag will be written when the data is available */
mca_btl_vader_fbox_set_header (MCA_BTL_VADER_FBOX_HDR(dst), 0, ep->fbox_out.seq++, data_size);
end += size;
if (OPAL_UNLIKELY(fbox_size == end)) {
/* toggle the high bit */
hbs = !hbs;
/* reset the end pointer to the beginning of the buffer */
end = MCA_BTL_VADER_FBOX_ALIGNMENT;
} else if (buffer_free > size) {
MCA_BTL_VADER_FBOX_HDR(ep->fbox_out.buffer + end)->ival = 0;
}
/* align the buffer */
ep->fbox_out.end = ((uint32_t) hbs << 31) | end;
opal_atomic_wmb ();
OPAL_THREAD_UNLOCK(&ep->lock);
return dst + sizeof (mca_btl_vader_fbox_hdr_t);
}
static inline void mca_btl_vader_fbox_send (unsigned char * restrict fbox, unsigned char tag)
{
/* ensure data writes have completed before we mark the data as available */
opal_atomic_wmb ();
/* the header proceeds the fbox buffer */
MCA_BTL_VADER_FBOX_HDR ((intptr_t) fbox)[-1].data.tag = tag;
}
static inline bool mca_btl_vader_fbox_sendi (mca_btl_base_endpoint_t *ep, unsigned char tag,
void * restrict header, const size_t header_size,
void * restrict payload, const size_t payload_size)
{
const size_t total_size = header_size + payload_size;
unsigned char * restrict fbox;
fbox = mca_btl_vader_reserve_fbox(ep, total_size);
if (OPAL_UNLIKELY(NULL == fbox)) {
return false;
}
memcpy (fbox, header, header_size);
if (payload) {
/* inline sends are typically just pml headers (due to MCA_BTL_FLAGS_SEND_INPLACE) */
memcpy (fbox + header_size, payload, payload_size);
}
/* mark the fbox as sent */
mca_btl_vader_fbox_send (fbox, tag);
/* send complete */
return true;
}
static inline bool mca_btl_vader_check_fboxes (void)
{
const unsigned int fbox_size = mca_btl_vader_component.fbox_size;
bool processed = false;
for (unsigned int i = 0 ; i < mca_btl_vader_component.num_fbox_in_endpoints ; ++i) {
mca_btl_base_endpoint_t *ep = mca_btl_vader_component.fbox_in_endpoints[i];
unsigned int start = ep->fbox_in.start & MCA_BTL_VADER_FBOX_OFFSET_MASK;
/* save the current high bit state */
bool hbs = MCA_BTL_VADER_FBOX_OFFSET_HBS(ep->fbox_in.start);
int poll_count;
for (poll_count = 0 ; poll_count <= MCA_BTL_VADER_POLL_COUNT ; ++poll_count) {
const mca_btl_vader_fbox_hdr_t hdr = {.ival = MCA_BTL_VADER_FBOX_HDR(ep->fbox_in.buffer + start)->ival};
/* check for a valid tag a sequence number */
if (0 == hdr.data.tag || hdr.data.seq != ep->fbox_in.seq) {
break;
}
++ep->fbox_in.seq;
/* force all prior reads to complete before continuing */
opal_atomic_rmb ();
BTL_VERBOSE(("got frag from %d with header {.tag = %d, .size = %d, .seq = %u} from offset %u",
ep->peer_smp_rank, hdr.data.tag, hdr.data.size, hdr.data.seq, start));
/* the 0xff tag indicates we should skip the rest of the buffer */
if (OPAL_LIKELY((0xfe & hdr.data.tag) != 0xfe)) {
mca_btl_base_segment_t segment;
mca_btl_base_descriptor_t desc = {.des_segments = &segment, .des_segment_count = 1};
const mca_btl_active_message_callback_t *reg =
mca_btl_base_active_message_trigger + hdr.data.tag;
/* fragment fits entirely in the remaining buffer space. some
* btl users do not handle fragmented data so we can't split
* the fragment without introducing another copy here. this
* limitation has not appeared to cause any performance
* degradation. */
segment.seg_len = hdr.data.size;
segment.seg_addr.pval = (void *) (ep->fbox_in.buffer + start + sizeof (hdr));
/* call the registered callback function */
reg->cbfunc(&mca_btl_vader.super, hdr.data.tag, &desc, reg->cbdata);
} else if (OPAL_LIKELY(0xfe == hdr.data.tag)) {
/* process fragment header */
fifo_value_t *value = (fifo_value_t *)(ep->fbox_in.buffer + start + sizeof (hdr));
mca_btl_vader_hdr_t *hdr = relative2virtual(*value);
mca_btl_vader_poll_handle_frag (hdr, ep);
}
start = (start + hdr.data.size + sizeof (hdr) + MCA_BTL_VADER_FBOX_ALIGNMENT_MASK) & ~MCA_BTL_VADER_FBOX_ALIGNMENT_MASK;
if (OPAL_UNLIKELY(fbox_size == start)) {
/* jump to the beginning of the buffer */
start = MCA_BTL_VADER_FBOX_ALIGNMENT;
/* toggle the high bit */
hbs = !hbs;
}
}
if (poll_count) {
BTL_VERBOSE(("left off at offset %u (hbs: %d)", start, hbs));
/* save where we left off */
/* let the sender know where we stopped */
opal_atomic_mb ();
ep->fbox_in.start = ep->fbox_in.startp[0] = ((uint32_t) hbs << 31) | start;
processed = true;
}
}
/* return the number of fragments processed */
return processed;
}
static inline void mca_btl_vader_try_fbox_setup (mca_btl_base_endpoint_t *ep, mca_btl_vader_hdr_t *hdr)
{
if (OPAL_UNLIKELY(NULL == ep->fbox_out.buffer && mca_btl_vader_component.fbox_threshold == OPAL_THREAD_ADD_SIZE_T (&ep->send_count, 1))) {
/* protect access to mca_btl_vader_component.segment_offset */
OPAL_THREAD_LOCK(&mca_btl_vader_component.lock);
if (mca_btl_vader_component.segment_size >= mca_btl_vader_component.segment_offset + mca_btl_vader_component.fbox_size &&
mca_btl_vader_component.fbox_max > mca_btl_vader_component.fbox_count) {
/* verify the remote side will accept another fbox */
if (0 <= opal_atomic_add_32 (&ep->fifo->fbox_available, -1)) {
void *fbox_base = mca_btl_vader_component.my_segment + mca_btl_vader_component.segment_offset;
mca_btl_vader_component.segment_offset += mca_btl_vader_component.fbox_size;
/* zero out the fast box */
memset (fbox_base, 0, mca_btl_vader_component.fbox_size);
mca_btl_vader_endpoint_setup_fbox_send (ep, fbox_base);
hdr->flags |= MCA_BTL_VADER_FLAG_SETUP_FBOX;
hdr->fbox_base = virtual2relative((char *) ep->fbox_out.buffer);
++mca_btl_vader_component.fbox_count;
} else {
opal_atomic_add_32 (&ep->fifo->fbox_available, 1);
}
opal_atomic_wmb ();
}
OPAL_THREAD_UNLOCK(&mca_btl_vader_component.lock);
}
}
#endif /* !defined(MCA_BTL_VADER_FBOX_H) */