Commit 7c683cf2b1aa038a2c4467856e2d3636b36b262b
2013-06-21T10:59:55
Use low latency usb transfers on the avalon, sleeping up to half a buffer's worth only if no data is returning to increase hashrate, abolish lost work and decrease CPU.
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diff --git a/driver-avalon.c b/driver-avalon.c
index f99850a..531a961 100644
--- a/driver-avalon.c
+++ b/driver-avalon.c
@@ -229,7 +229,7 @@ static bool avalon_decode_nonce(struct thr_info *thr, struct cgpu_info *avalon,
static void wait_avalon_ready(struct cgpu_info *avalon)
{
while (avalon_buffer_full(avalon)) {
- nmsleep(AVALON_READ_TIMEOUT);
+ nmsleep(40);
}
}
@@ -240,11 +240,6 @@ static int avalon_read(struct cgpu_info *avalon, unsigned char *buf,
char readbuf[AVALON_READBUF_SIZE];
int err, amount, ofs = 2, cp;
- /* If the buffer is ready to take more work, yield once in case the
- * write thread is waiting to be scheduled. */
- if (!avalon_buffer_full(avalon))
- nmsleep(AVALON_READ_TIMEOUT);
-
err = usb_read_once_timeout(avalon, readbuf, readsize, &amount, timeout, ep);
applog(LOG_DEBUG, "%s%i: Get avalon read got err %d",
avalon->drv->name, avalon->device_id, err);
@@ -493,7 +488,7 @@ static void avalon_initialise(struct cgpu_info *avalon)
// Set latency
err = usb_transfer(avalon, FTDI_TYPE_OUT, FTDI_REQUEST_LATENCY,
- AVALON_READ_TIMEOUT, interface, C_LATENCY);
+ AVALON_LATENCY, interface, C_LATENCY);
applog(LOG_DEBUG, "%s%i: latency got err %d",
avalon->drv->name, avalon->device_id, err);
@@ -742,18 +737,20 @@ static void *avalon_get_results(void *userdata)
{
struct cgpu_info *avalon = (struct cgpu_info *)userdata;
struct avalon_info *info = avalon->device_data;
+ int offset = 0, read_delay = 0, ret = 0;
const int rsize = AVALON_FTDI_READSIZE;
char readbuf[AVALON_READBUF_SIZE];
struct thr_info *thr = info->thr;
+ struct timeval tv_start, tv_end;
char threadname[24];
- int offset = 0;
snprintf(threadname, 24, "ava_recv/%d", avalon->device_id);
RenameThread(threadname);
while (likely(!avalon->shutdown)) {
unsigned char buf[rsize];
- int ret;
+ struct timeval tv_diff;
+ int us_diff;
if (offset >= (int)AVALON_READ_SIZE)
avalon_parse_results(avalon, info, thr, readbuf, &offset);
@@ -773,6 +770,20 @@ static void *avalon_get_results(void *userdata)
offset = 0;
}
+ /* As the usb read returns after just 1ms, sleep long enough
+ * to leave the interface idle for writes to occur, but do not
+ * sleep if we have been receiving data as more may be coming. */
+ if (ret < 1) {
+ cgtime(&tv_end);
+ timersub(&tv_end, &tv_start, &tv_diff);
+ /* Assume it has not been > 1 second so ignore tv_sec */
+ us_diff = tv_diff.tv_usec;
+ read_delay = AVALON_READ_TIMEOUT * 1000 - us_diff;
+ if (likely(read_delay >= 1000))
+ nusleep(read_delay);
+ }
+
+ cgtime(&tv_start);
ret = avalon_read(avalon, buf, rsize, AVALON_READ_TIMEOUT,
C_AVALON_READ);
diff --git a/driver-avalon.h b/driver-avalon.h
index b5ff3e5..b77a330 100644
--- a/driver-avalon.h
+++ b/driver-avalon.h
@@ -34,7 +34,8 @@
#define AVALON_FTDI_READSIZE 510
#define AVALON_READBUF_SIZE 8192
#define AVALON_RESET_TIMEOUT 100
-#define AVALON_READ_TIMEOUT 10
+#define AVALON_READ_TIMEOUT 18 /* Enough to only half fill the buffer */
+#define AVALON_LATENCY 1
struct avalon_task {
uint8_t reset :1;