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ethervirtio: fix queue notifications and interrupt flags, avoid useless notifications

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bug: Rnointerrupt was used on Vqueue.used.flags instead of
Vqueue.avail.flags.

introduce vqnotify() function that notifies the device
about available ring advancement.

avoid queue notifications there that can be slow by
checking Unonotify flag in Vqueue.used.flags.

keep track of the number of notifications in the queue.
This commit is contained in:
cinap_lenrek 2014-12-09 03:23:53 +01:00
parent 469a10f1d9
commit a0bb446d75
1 changed files with 26 additions and 10 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

36
sys/src/9/pc/ethervirtio.c
View file

@ -137,6 +137,7 @@ struct Vqueue
u16int lastused;
uint nintr;
uint nnote;
};
struct Ctlr {
@ -168,6 +169,19 @@ vhasroom(void *v)
return q->lastused != q->used->idx;
}
static void
vqnotify(Ctlr *ctlr, int x)
{
Vqueue *q;
coherence();
q = &ctlr->queue[x];
if(q->used->flags & Unonotify)
return;
q->nnote++;
outs(ctlr->port+Qnotify, x);
}
static void
txproc(void *v)
{
@ -201,7 +215,7 @@ txproc(void *v)
q->desc[j].flags = 0;
}
q->used->flags &= ~Rnointerrupt;
q->avail->flags &= ~Rnointerrupt;
while(waserror())
;
@ -236,7 +250,7 @@ txproc(void *v)
q->desc[j].len = BLEN(b);
coherence();
q->avail->idx++;
outs(ctlr->port+Qnotify, Vtxq);
vqnotify(ctlr, Vtxq);
}
pexit("ether out queue closed", 1);
@ -275,7 +289,7 @@ rxproc(void *v)
q->desc[j].flags = Dwrite;
}
q->used->flags &= ~Rnointerrupt;
q->avail->flags &= ~Rnointerrupt;
while(waserror())
;
@ -294,8 +308,8 @@ rxproc(void *v)
q->desc[j].len = BALLOC(b);
coherence();
q->avail->idx++;
outs(ctlr->port+Qnotify, Vrxq);
} while(q->avail->idx != q->used->idx);
vqnotify(ctlr, Vrxq);
/* wait for any packets to complete */
if(!vhasroom(q))
@ -359,13 +373,13 @@ vctlcmd(Ether *edev, uchar class, uchar cmd, uchar *data, int ndata)
q->availent[i] = 0;
coherence();
q->used->flags &= ~Rnointerrupt;
q->avail->flags &= ~Rnointerrupt;
q->avail->idx++;
outs(ctlr->port+Qnotify, Vctlq);
vqnotify(ctlr, Vctlq);
while(!vhasroom(q))
sleep(q, vhasroom, q);
q->lastused = q->used->idx;
q->used->flags |= Rnointerrupt;
q->avail->flags |= Rnointerrupt;
qunlock(&ctlr->ctllock);
poperror();
@ -440,8 +454,9 @@ ifstat(Ether *edev, void *a, long n, ulong offset)
for(i = 0; i < ctlr->nqueue; i++){
q = &ctlr->queue[i];
l += snprint(p+l, READSTR-l, "vq%d %#p size %d avail->idx %d used->idx %d lastused %hud nintr %ud\n",
i, q, q->qsize, q->avail->idx, q->used->idx, q->lastused, q->nintr);
l += snprint(p+l, READSTR-l,
"vq%d %#p size %d avail->idx %d used->idx %d lastused %hud nintr %ud nnote %ud\n",
i, q, q->qsize, q->avail->idx, q->used->idx, q->lastused, q->nintr, q->nnote);
}
n = readstr(offset, a, n, p);
@ -520,7 +535,8 @@ initqueue(Vqueue *q, int size)
q->qmask = q->qsize - 1;
q->lastused = q->avail->idx = q->used->idx = 0;
q->used->flags |= Rnointerrupt;
q->avail->flags |= Rnointerrupt;
return 0;
}