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Commit e4cf3aa8 authored by David Engraf's avatar David Engraf Committed by Greg Kroah-Hartman
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USB: increase cdc-acm write throughput 



the following patch uses 16 write urbs and a writsize of wMaxPacketSize
* 20.  With this patch I get the maximum througput from my linux system
with 20MB/sec read and 15 MB/sec write (full speed 1 MB/sec both)

I also deleted the flag URB_NO_FSBR for the writeurbs, because this
makes my full speed devices significant slower.

Signed-off-by: default avatarDavid Engraf <david.engraf@netcom.eu>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 28d1dfad

drivers/usb/class/cdc-acm.c

+41 −40
Original line number Diff line number Diff line
@@ -31,6 +31,7 @@ 
 *	v0.23 - use softirq for rx processing, as needed by tty layer

 *	v0.24 - change probe method to evaluate CDC union descriptor

 *	v0.25 - downstream tasks paralelized to maximize throughput

 *	v0.26 - multiple write urbs, writesize increased

 */



/*
@@ -72,7 +73,7 @@ 
/*

 * Version Information

 */

#define DRIVER_VERSION "v0.25"

#define DRIVER_VERSION "v0.26"

#define DRIVER_AUTHOR "Armin Fuerst, Pavel Machek, Johannes Erdfelt, Vojtech Pavlik, David Kubicek"

#define DRIVER_DESC "USB Abstract Control Model driver for USB modems and ISDN adapters"
@@ -118,7 +119,7 @@ static int acm_wb_alloc(struct acm *acm) 
	int i, wbn;

	struct acm_wb *wb;



	wbn = acm->write_current;

	wbn = 0;

	i = 0;

	for (;;) {

		wb = &acm->wb[wbn];
@@ -132,11 +133,6 @@ static int acm_wb_alloc(struct acm *acm) 
	}

}



static void acm_wb_free(struct acm *acm, int wbn)

{

	acm->wb[wbn].use = 0;

}



static int acm_wb_is_avail(struct acm *acm)

{

	int i, n;
@@ -156,26 +152,22 @@ static inline int acm_wb_is_used(struct acm *acm, int wbn) 
/*

 * Finish write.

 */

static void acm_write_done(struct acm *acm)

static void acm_write_done(struct acm *acm, struct acm_wb *wb)

{

	unsigned long flags;

	int wbn;



	spin_lock_irqsave(&acm->write_lock, flags);

	acm->write_ready = 1;

	wbn = acm->write_current;

	acm_wb_free(acm, wbn);

	acm->write_current = (wbn + 1) % ACM_NW;

	wb->use = 0;

	spin_unlock_irqrestore(&acm->write_lock, flags);

}



/*

 * Poke write.

 */

static int acm_write_start(struct acm *acm)

static int acm_write_start(struct acm *acm, int wbn)

{

	unsigned long flags;

	int wbn;

	struct acm_wb *wb;

	int rc;
@@ -190,24 +182,24 @@ static int acm_write_start(struct acm *acm) 
		return 0;	/* A white lie */

	}



	wbn = acm->write_current;

	if (!acm_wb_is_used(acm, wbn)) {

		spin_unlock_irqrestore(&acm->write_lock, flags);

		return 0;

	}

	wb = &acm->wb[wbn];



	if(acm_wb_is_avail(acm) <= 1)

		acm->write_ready = 0;

	spin_unlock_irqrestore(&acm->write_lock, flags);



	acm->writeurb->transfer_buffer = wb->buf;

	acm->writeurb->transfer_dma = wb->dmah;

	acm->writeurb->transfer_buffer_length = wb->len;

	acm->writeurb->dev = acm->dev;

	wb->urb->transfer_buffer = wb->buf;

	wb->urb->transfer_dma = wb->dmah;

	wb->urb->transfer_buffer_length = wb->len;

	wb->urb->dev = acm->dev;



	if ((rc = usb_submit_urb(acm->writeurb, GFP_ATOMIC)) < 0) {

	if ((rc = usb_submit_urb(wb->urb, GFP_ATOMIC)) < 0) {

		dbg("usb_submit_urb(write bulk) failed: %d", rc);

		acm_write_done(acm);

		acm_write_done(acm, wb);

	}

	return rc;

}
@@ -450,12 +442,13 @@ urbs: 
/* data interface wrote those outgoing bytes */

static void acm_write_bulk(struct urb *urb)

{

	struct acm *acm = (struct acm *)urb->context;

	struct acm *acm;

	struct acm_wb *wb = (struct acm_wb *)urb->context;



	dbg("Entering acm_write_bulk with status %d", urb->status);



	acm_write_done(acm);

	acm_write_start(acm);

	acm = wb->instance;

	acm_write_done(acm, wb);

	if (ACM_READY(acm))

		schedule_work(&acm->work);

}
@@ -557,7 +550,8 @@ static void acm_tty_unregister(struct acm *acm) 
	usb_put_intf(acm->control);

	acm_table[acm->minor] = NULL;

	usb_free_urb(acm->ctrlurb);

	usb_free_urb(acm->writeurb);

	for (i = 0; i < ACM_NW; i++)

		usb_free_urb(acm->wb[i].urb);

	for (i = 0; i < nr; i++)

		usb_free_urb(acm->ru[i].urb);

	kfree(acm->country_codes);
@@ -578,7 +572,8 @@ static void acm_tty_close(struct tty_struct *tty, struct file *filp) 
		if (acm->dev) {

			acm_set_control(acm, acm->ctrlout = 0);

			usb_kill_urb(acm->ctrlurb);

			usb_kill_urb(acm->writeurb);

			for (i = 0; i < ACM_NW; i++)

				usb_kill_urb(acm->wb[i].urb);

			for (i = 0; i < nr; i++)

				usb_kill_urb(acm->ru[i].urb);

			usb_autopm_put_interface(acm->control);
@@ -606,7 +601,6 @@ static int acm_tty_write(struct tty_struct *tty, const unsigned char *buf, int c 
	spin_lock_irqsave(&acm->write_lock, flags);

	if ((wbn = acm_wb_alloc(acm)) < 0) {

		spin_unlock_irqrestore(&acm->write_lock, flags);

		acm_write_start(acm);

		return 0;

	}

	wb = &acm->wb[wbn];
@@ -617,7 +611,7 @@ static int acm_tty_write(struct tty_struct *tty, const unsigned char *buf, int c 
	wb->len = count;

	spin_unlock_irqrestore(&acm->write_lock, flags);



	if ((stat = acm_write_start(acm)) < 0)

	if ((stat = acm_write_start(acm, wbn)) < 0)

		return stat;

	return count;

}
@@ -977,7 +971,7 @@ skip_normal_probe: 


	ctrlsize = le16_to_cpu(epctrl->wMaxPacketSize);

	readsize = le16_to_cpu(epread->wMaxPacketSize)* ( quirks == SINGLE_RX_URB ? 1 : 2);

	acm->writesize = le16_to_cpu(epwrite->wMaxPacketSize);

	acm->writesize = le16_to_cpu(epwrite->wMaxPacketSize) * 20;

	acm->control = control_interface;

	acm->data = data_interface;

	acm->minor = minor;
@@ -1032,12 +1026,21 @@ skip_normal_probe: 
			goto alloc_fail7;

		}

	}

	acm->writeurb = usb_alloc_urb(0, GFP_KERNEL);

	if (!acm->writeurb) {

		dev_dbg(&intf->dev, "out of memory (writeurb kmalloc)\n");

	for(i = 0; i < ACM_NW; i++)

	{

		struct acm_wb *snd = &(acm->wb[i]);



		if (!(snd->urb = usb_alloc_urb(0, GFP_KERNEL))) {

			dev_dbg(&intf->dev, "out of memory (write urbs usb_alloc_urb)");

			goto alloc_fail7;

		}



		usb_fill_bulk_urb(snd->urb, usb_dev, usb_sndbulkpipe(usb_dev, epwrite->bEndpointAddress),

				NULL, acm->writesize, acm_write_bulk, snd);

		snd->urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;

		snd->instance = acm;

	}



	usb_set_intfdata (intf, acm);



	i = device_create_file(&intf->dev, &dev_attr_bmCapabilities);
@@ -1071,10 +1074,6 @@ skip_countries: 
	acm->ctrlurb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;

	acm->ctrlurb->transfer_dma = acm->ctrl_dma;



	usb_fill_bulk_urb(acm->writeurb, usb_dev, usb_sndbulkpipe(usb_dev, epwrite->bEndpointAddress),

			  NULL, acm->writesize, acm_write_bulk, acm);

	acm->writeurb->transfer_flags |= URB_NO_FSBR | URB_NO_TRANSFER_DMA_MAP;



	dev_info(&intf->dev, "ttyACM%d: USB ACM device\n", minor);



	acm_set_control(acm, acm->ctrlout);
@@ -1092,7 +1091,8 @@ skip_countries: 


	return 0;

alloc_fail8:

	usb_free_urb(acm->writeurb);

	for (i = 0; i < ACM_NW; i++)

		usb_free_urb(acm->wb[i].urb);

alloc_fail7:

	for (i = 0; i < num_rx_buf; i++)

		usb_buffer_free(usb_dev, acm->readsize, acm->rb[i].base, acm->rb[i].dma);
@@ -1116,7 +1116,8 @@ static void stop_data_traffic(struct acm *acm) 
	tasklet_disable(&acm->urb_task);



	usb_kill_urb(acm->ctrlurb);

	usb_kill_urb(acm->writeurb);

	for(i = 0; i < ACM_NW; i++)

		usb_kill_urb(acm->wb[i].urb);

	for (i = 0; i < acm->rx_buflimit; i++)

		usb_kill_urb(acm->ru[i].urb);

drivers/usb/class/cdc-acm.h

+4 −3
Original line number Diff line number Diff line
@@ -59,7 +59,7 @@ 
 * when processing onlcr, so we only need 2 buffers. These values must be

 * powers of 2.

 */

#define ACM_NW  2

#define ACM_NW  16

#define ACM_NR  16



struct acm_wb {
@@ -67,6 +67,8 @@ struct acm_wb { 
	dma_addr_t dmah;

	int len;

	int use;

	struct urb		*urb;

	struct acm		*instance;

};



struct acm_rb {
@@ -88,7 +90,7 @@ struct acm { 
	struct usb_interface *control;			/* control interface */

	struct usb_interface *data;			/* data interface */

	struct tty_struct *tty;				/* the corresponding tty */

	struct urb *ctrlurb, *writeurb;			/* urbs */

	struct urb *ctrlurb;			/* urbs */

	u8 *ctrl_buffer;				/* buffers of urbs */

	dma_addr_t ctrl_dma;				/* dma handles of buffers */

	u8 *country_codes;				/* country codes from device */
@@ -103,7 +105,6 @@ struct acm { 
	struct list_head spare_read_urbs;

	struct list_head spare_read_bufs;

	struct list_head filled_read_bufs;

	int write_current;				/* current write buffer */

	int write_used;					/* number of non-empty write buffers */

	int write_ready;				/* write urb is not running */

	spinlock_t write_lock;