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Commit dced3a05 authored by Ed L. Cashin's avatar Ed L. Cashin Committed by Greg Kroah-Hartman
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aoe: improve retransmission heuristics 



Add a dynamic minimum timer for better retransmission behavior.

Signed-off-by: default avatar"Ed L. Cashin" <ecashin@coraid.com>
Acked-by: default avatarAlan Cox <alan@redhat.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent ddec63e8

drivers/block/aoe/aoe.h

+4 −3
Original line number Diff line number Diff line
@@ -125,8 +125,10 @@ struct aoedev { 
	ulong sysminor;

	ulong aoemajor;

	ulong aoeminor;

	ulong nopen;		/* (bd_openers isn't available without sleeping) */

	ulong rttavg;		/* round trip average of requests/responses */

	u16 nopen;		/* (bd_openers isn't available without sleeping) */

	u16 lasttag;		/* last tag sent */

	u16 rttavg;		/* round trip average of requests/responses */

	u16 mintimer;

	u16 fw_ver;		/* version of blade's firmware */

	u16 maxbcnt;

	struct work_struct work;/* disk create work struct */
@@ -142,7 +144,6 @@ struct aoedev { 
	mempool_t *bufpool;	/* for deadlock-free Buf allocation */

	struct list_head bufq;	/* queue of bios to work on */

	struct buf *inprocess;	/* the one we're currently working on */

	ulong lasttag;		/* last tag sent */

	ushort lostjumbo;

	ushort nframes;		/* number of frames below */

	struct frame *frames;

drivers/block/aoe/aoecmd.c

+13 −3
Original line number Diff line number Diff line
@@ -461,10 +461,17 @@ calc_rttavg(struct aoedev *d, int rtt) 
	register long n;



	n = rtt;

	if (n < 0) {

		n = -rtt;

		if (n < MINTIMER)

			n = MINTIMER;

		else if (n > MAXTIMER)

			n = MAXTIMER;

		d->mintimer += (n - d->mintimer) >> 1;

	} else if (n < d->mintimer)

		n = d->mintimer;

	else if (n > MAXTIMER)

		n = MAXTIMER;



	/* g == .25; cf. Congestion Avoidance and Control, Jacobson & Karels; 1988 */

	n -= d->rttavg;
@@ -498,8 +505,10 @@ aoecmd_ata_rsp(struct sk_buff *skb) 


	spin_lock_irqsave(&d->lock, flags);



	f = getframe(d, be32_to_cpu(hin->tag));

	n = be32_to_cpu(hin->tag);

	f = getframe(d, n);

	if (f == NULL) {

		calc_rttavg(d, -tsince(n));

		spin_unlock_irqrestore(&d->lock, flags);

		snprintf(ebuf, sizeof ebuf,

			"%15s e%d.%d    tag=%08x@%08lx\n",
@@ -724,6 +733,7 @@ aoecmd_cfg_rsp(struct sk_buff *skb) 
		return;

	}

	d->flags |= DEVFL_PAUSE;	/* force pause */

	d->mintimer = MINTIMER;

	d->fw_ver = be16_to_cpu(ch->fwver);



	/* check for already outstanding ataid */