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[commtech] Simplify if's in send() 

Test sender_ptr against the end of the current buffer via
channel->sender_ptr_end
This commit is contained in:
Thomas Preud'homme 2011-06-06 13:34:01 +02:00 committed by Thomas Preud'homme
parent a20c9a8a21
commit 7c4a484989
2 changed files with 25 additions and 38 deletions
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55
communication_techniques/include/batch_queue_common_comm.h
View File

@ -15,64 +15,45 @@ struct channel
{ {
/* buf must be the first field to allow the buf_mask test */ /* buf must be the first field to allow the buf_mask test */
void * volatile buf[2][BUF_SIZE / sizeof(void *)] __attribute__ ((aligned (CACHE_LINE_SIZE))); void * volatile buf[2][BUF_SIZE / sizeof(void *)] __attribute__ ((aligned (CACHE_LINE_SIZE)));
struct channel *mapping1; /* accesses to buf[0] and state */
struct channel *mapping2; /* accesses to buf[1] */
uintptr_t buf_mask;
int unused[20] __attribute__ ((aligned (CACHE_LINE_SIZE))); int unused[20] __attribute__ ((aligned (CACHE_LINE_SIZE)));
volatile unsigned int state:1 __attribute__ ((aligned (CACHE_LINE_SIZE))); volatile unsigned int state:1 __attribute__ ((aligned (CACHE_LINE_SIZE)));
/* accesses to buf[0] and state */
struct channel *mapping1 __attribute__ ((aligned (CACHE_LINE_SIZE)));
/* accesses to buf[1] */
struct channel *mapping2;
void * volatile *buf_end1;
void * volatile *buf_end2;
void * volatile *sender_ptr __attribute__ ((aligned (CACHE_LINE_SIZE))); void * volatile *sender_ptr __attribute__ ((aligned (CACHE_LINE_SIZE)));
void * volatile *sender_ptr_end;
void * volatile *receiver_ptr __attribute__ ((aligned (CACHE_LINE_SIZE))); void * volatile *receiver_ptr __attribute__ ((aligned (CACHE_LINE_SIZE)));
}; };
#ifndef _BATCH_QUEUE_C_
#ifndef PAGE_SIZE_HELPER
#define PAGE_SIZE_HELPER 1
uintptr_t _bq_page_mask;
void *create_comm_channel_internal(void);
static void *create_comm_channel_helper(void) __attribute__ ((unused));
static void *create_comm_channel_helper(void)
{
int ret;
struct channel *channel;
ret = sysconf(_SC_PAGESIZE);
if (ret == -1)
return NULL;
_bq_page_mask = ~(ret - 1);
channel = create_comm_channel_internal();
channel->buf_mask = sizeof channel->buf[0] - 1;
return channel;
}
#else
extern unsigned int _bq_page_mask;
#endif /* PAGE_SIZE_HELPER */
#define create_comm_channel() create_comm_channel_helper()
__BEGIN_DECLS __BEGIN_DECLS
static inline void send(struct channel *channel, void **addr) static inline void send(struct channel *channel, void **addr)
{ {
uintptr_t sender_ptr_high;
*channel->sender_ptr++ = addr; *channel->sender_ptr++ = addr;
if (unlikely(!((uintptr_t) channel->sender_ptr & channel->buf_mask))) if (unlikely(channel->sender_ptr == channel->sender_ptr_end))
{ {
while (channel->state); while (channel->state);
channel->state = 1; channel->state = 1;
sender_ptr_high = if (channel->sender_ptr_end == channel->buf_end1)
(uintptr_t) channel->sender_ptr & _bq_page_mask; {
if ((void *) sender_ptr_high == channel->mapping1)
channel->sender_ptr = channel->mapping2->buf[1]; channel->sender_ptr = channel->mapping2->buf[1];
channel->sender_ptr_end = channel->buf_end2;
}
else else
channel->sender_ptr = channel->mapping1->buf[0]; {
channel->sender_ptr = channel->buf[0];
channel->sender_ptr_end = channel->buf_end1;
}
} }
} }
__END_DECLS __END_DECLS
#endif /* _BATCH_QUEUE_C_ */
#endif #endif

8
communication_techniques/src/communication/batch_queue.c
View File

@ -23,7 +23,7 @@ static int nb_buf_entries;
static unsigned int page_size; static unsigned int page_size;
void *create_comm_channel_internal(void) void *create_comm_channel(void)
{ {
int ret, shm_fd; int ret, shm_fd;
static int chan_idx = 0; static int chan_idx = 0;
@ -83,6 +83,12 @@ void *create_comm_channel_internal(void)
channel1->sender_ptr = channel1->buf[0]; channel1->sender_ptr = channel1->buf[0];
channel1->receiver_ptr = channel1->buf[0]; channel1->receiver_ptr = channel1->buf[0];
channel1->buf_end1 = channel1->buf[0] +
(sizeof channel1->buf[0] / sizeof channel1->buf[0][0]);
channel1->buf_end2 = channel1->mapping2->buf[1] +
(sizeof channel1->buf[1] / sizeof channel1->buf[1][0]);
channel1->sender_ptr_end = channel1->buf_end1;
buf_mask = sizeof channel1->buf[0] - 1; buf_mask = sizeof channel1->buf[0] - 1;
nb_buf_entries = sizeof channel1->buf[0] / sizeof channel1->buf[0][0]; nb_buf_entries = sizeof channel1->buf[0] / sizeof channel1->buf[0][0];
close_file: close_file: