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xpp: improve handling of USB sluggishness 

* Drop PCM during sluggish events:
  - Drop both rx/tx (was only tx)
  - Drop almost all pcm until sluggishness stops (used to drop only
    single pcm each time).
  - Renamed: "drop_next_pcm" -> "drop_pcm" (to match new semantics)
  - Still allow "keep alive" PCM so Astribank will not reset FXS high-voltage.
    The "sluggish_pcm_keepalive" parameter set the rate (1/50 by default)
  - Added rx/tx drop statistics counters
  - Removed "pcm_tx_drops" (replaced by new statistics counters)

* Also improved format of /proc/xpp/XBUS-*/xpp_usb:
  - Show cummulative number of sluggish events.
  - Clearly show range (in usec) of usb_tx_delay[]

Signed-off-by: Tzafrir Cohen <tzafrir.cohen@xorcom.com>
This commit is contained in:
Oron Peled 2015-07-20 09:11:07 +00:00 committed by Tzafrir Cohen
parent fac77101fb
commit 404a67d089
1 changed files with 59 additions and 20 deletions
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79
drivers/dahdi/xpp/xpp_usb.c
View File

@ -49,7 +49,9 @@ static DEF_PARM(int, debug, 0, 0644, "Print DBG statements");
static DEF_PARM(int, usb1, 0, 0644, "Allow using USB 1.1 interfaces");
static DEF_PARM(uint, tx_sluggish, 2000, 0644, "A sluggish transmit (usec)");
static DEF_PARM(uint, drop_pcm_after, 6, 0644,
"Number of consecutive tx_sluggish to drop a PCM frame");
"Number of consecutive tx_sluggish to start dropping PCM");
static DEF_PARM(uint, sluggish_pcm_keepalive, 50, 0644,
"During sluggish -- Keep-alive PCM (1 every #)");
#include "dahdi_debug.h"
@ -117,6 +119,8 @@ enum {
XUSB_N_TX_FRAMES,
XUSB_N_RX_ERRORS,
XUSB_N_TX_ERRORS,
XUSB_N_RX_DROPS,
XUSB_N_TX_DROPS,
XUSB_N_RCV_ZERO_LEN,
};
@ -127,8 +131,14 @@ enum {
static struct xusb_counters {
char *name;
} xusb_counters[] = {
C_(RX_FRAMES), C_(TX_FRAMES), C_(RX_ERRORS), C_(TX_ERRORS),
C_(RCV_ZERO_LEN),};
C_(RX_FRAMES),
C_(TX_FRAMES),
C_(RX_ERRORS),
C_(TX_ERRORS),
C_(RX_DROPS),
C_(TX_DROPS),
C_(RCV_ZERO_LEN),
};
#undef C_
@ -194,8 +204,7 @@ struct xusb {
unsigned int max_tx_delay;
uint usb_tx_delay[NUM_BUCKETS];
uint sluggish_debounce;
bool drop_next_pcm; /* due to sluggishness */
atomic_t pcm_tx_drops;
bool drop_pcm; /* due to sluggishness */
atomic_t usb_sluggish_count;
const char *manufacturer;
@ -400,12 +409,23 @@ static int xframe_send_pcm(xbus_t *xbus, xframe_t *xframe)
BUG_ON(!xframe);
xusb = xusb_of(xbus);
BUG_ON(!xusb);
if (xusb->drop_next_pcm) {
FREE_SEND_XFRAME(xbus, xframe); /* return to pool */
xusb->drop_next_pcm = 0;
return -EIO;
if (xusb->drop_pcm) {
static int rate_limit;
if ((rate_limit++ % 1000) == 0)
XUSB_ERR(xusb, "Sluggish USB: drop tx-pcm (%d)\n",
rate_limit);
/* Let trickle of TX-PCM, so Astribank will not reset */
if (sluggish_pcm_keepalive &&
((rate_limit % sluggish_pcm_keepalive) != 0)) {
XUSB_COUNTER(xusb, TX_DROPS)++;
goto err;
}
}
return do_send_xframe(xbus, xframe);
err:
FREE_SEND_XFRAME(xbus, xframe); /* return to pool */
return -EIO;
}
/*
@ -674,7 +694,6 @@ static int xusb_probe(struct usb_interface *interface,
sema_init(&xusb->sem, 1);
atomic_set(&xusb->pending_writes, 0);
atomic_set(&xusb->pending_reads, 0);
atomic_set(&xusb->pcm_tx_drops, 0);
atomic_set(&xusb->usb_sluggish_count, 0);
xusb->udev = udev;
xusb->interface = interface;
@ -878,7 +897,6 @@ static void xpp_send_callback(USB_PASS_CB(urb))
i = NUM_BUCKETS - 1;
xusb->usb_tx_delay[i]++;
if (unlikely(usec > tx_sluggish)) {
atomic_inc(&xusb->usb_sluggish_count);
if (xusb->sluggish_debounce++ > drop_pcm_after) {
static int rate_limit;
@ -888,12 +906,14 @@ static void xpp_send_callback(USB_PASS_CB(urb))
"Sluggish USB. Dropping next PCM frame "
"(pending_writes=%d)\n",
writes);
atomic_inc(&xusb->pcm_tx_drops);
xusb->drop_next_pcm = 1;
atomic_inc(&xusb->usb_sluggish_count);
xusb->drop_pcm = 1;
xusb->sluggish_debounce = 0;
}
} else
} else {
xusb->sluggish_debounce = 0;
xusb->drop_pcm = 0;
}
/* sync/async unlink faults aren't errors */
if (urb->status
&& !(urb->status == -ENOENT || urb->status == -ECONNRESET)) {
@ -956,6 +976,26 @@ static void xpp_receive_callback(USB_PASS_CB(urb))
// if (debug)
// dump_xframe("USB_FRAME_RECEIVE", xbus, xframe, debug);
XUSB_COUNTER(xusb, RX_FRAMES)++;
if (xusb->drop_pcm) {
/* some protocol analysis */
static int rate_limit;
xpacket_t *pack = (xpacket_t *)(xframe->packets);
bool is_pcm = XPACKET_IS_PCM(pack);
if (is_pcm) {
if ((rate_limit++ % 1000) == 0)
XUSB_ERR(xusb,
"Sluggish USB: drop rx-pcm (%d)\n",
rate_limit);
/* Let trickle of RX-PCM, so Astribank will not reset */
if (sluggish_pcm_keepalive &&
((rate_limit % sluggish_pcm_keepalive)
!= 0)) {
XUSB_COUNTER(xusb, RX_DROPS)++;
goto err;
}
}
}
/* Send UP */
xbus_receive_xframe(xbus, xframe);
end:
@ -1061,17 +1101,16 @@ static int xusb_read_proc_show(struct seq_file *sfile, void *data)
stamp_last_pcm_read, accumulate_diff);
#endif
memcpy(usb_tx_delay, xusb->usb_tx_delay, sizeof(usb_tx_delay));
seq_printf(sfile, "usb_tx_delay[%d,%d,%d]: ", USEC_BUCKET,
BUCKET_START, NUM_BUCKETS);
seq_printf(sfile, "usb_tx_delay[%dus - %dus]: ",
USEC_BUCKET * BUCKET_START,
USEC_BUCKET * NUM_BUCKETS);
for (i = BUCKET_START; i < NUM_BUCKETS; i++) {
seq_printf(sfile, "%6d ", usb_tx_delay[i]);
if (i == mark_limit)
seq_printf(sfile, "| ");
}
seq_printf(sfile, "\nPCM_TX_DROPS: %5d (sluggish: %d)\n",
atomic_read(&xusb->pcm_tx_drops),
atomic_read(&xusb->usb_sluggish_count)
);
seq_printf(sfile, "\nSluggish events: %d\n",
atomic_read(&xusb->usb_sluggish_count));
seq_printf(sfile, "\nCOUNTERS:\n");
for (i = 0; i < XUSB_COUNTER_MAX; i++) {
seq_printf(sfile, "\t%-15s = %d\n", xusb_counters[i].name,