[PATCH 1/7] [I/OAT] Push pending transactions to hardware more frequently

[PATCH 1/7] [I/OAT] Push pending transactions to hardware more frequently

[Chris Leech]

Every 20 descriptors turns out to be to few append commands with
newer/faster CPUs.  Pushing every 4 still cuts down on MMIO writes to an
acceptable level without letting the DMA engine run out of work.

Signed-off-by: Chris Leech <christopher.leech@intel.com>
---

 drivers/dma/ioatdma.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/dma/ioatdma.c b/drivers/dma/ioatdma.c
index dbd4d6c..be4fdd7 100644
--- a/drivers/dma/ioatdma.c
+++ b/drivers/dma/ioatdma.c
@@ -310,7 +310,7 @@ static dma_cookie_t do_ioat_dma_memcpy(s
 	list_splice_init(&new_chain, ioat_chan->used_desc.prev);
 
 	ioat_chan->pending += desc_count;
-	if (ioat_chan->pending >= 20) {
+	if (ioat_chan->pending >= 4) {
 		append = 1;
 		ioat_chan->pending = 0;
 	}
@@ -818,7 +818,7 @@ static void __devexit ioat_remove(struct
 }
 
 /* MODULE API */
-MODULE_VERSION("1.7");
+MODULE_VERSION("1.9");
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Intel Corporation");
 

[PATCH 2/7] [I/OAT] Only offload copies for TCP when there will be a context switch

[Chris Leech]

The performance wins come with having the DMA copy engine doing the copies
in parallel with the context switch.  If there is enough data ready on the
socket at recv time just use a regular copy.

Signed-off-by: Chris Leech <christopher.leech@intel.com>
---

 net/ipv4/tcp.c |   10 +++++++---
 1 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 934396b..36f6b64 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -1105,6 +1105,8 @@ int tcp_recvmsg(struct kiocb *iocb, stru
 	long timeo;
 	struct task_struct *user_recv = NULL;
 	int copied_early = 0;
+	int available = 0;
+	struct sk_buff *skb;
 
 	lock_sock(sk);
 
@@ -1131,7 +1133,11 @@ int tcp_recvmsg(struct kiocb *iocb, stru
 #ifdef CONFIG_NET_DMA
 	tp->ucopy.dma_chan = NULL;
 	preempt_disable();
-	if ((len > sysctl_tcp_dma_copybreak) && !(flags & MSG_PEEK) &&
+	skb = skb_peek_tail(&sk->sk_receive_queue);
+	if (skb)
+		available = TCP_SKB_CB(skb)->seq + skb->len - (*seq);
+	if ((available < target) &&
+	    (len > sysctl_tcp_dma_copybreak) && !(flags & MSG_PEEK) &&
 	    !sysctl_tcp_low_latency && __get_cpu_var(softnet_data).net_dma) {
 		preempt_enable_no_resched();
 		tp->ucopy.pinned_list = dma_pin_iovec_pages(msg->msg_iov, len);
@@ -1140,7 +1146,6 @@ int tcp_recvmsg(struct kiocb *iocb, stru
 #endif
 
 	do {
-		struct sk_buff *skb;
 		u32 offset;
 
 		/* Are we at urgent data? Stop if we have read anything or have SIGURG pending. */
@@ -1428,7 +1433,6 @@ skip_copy:
 
 #ifdef CONFIG_NET_DMA
 	if (tp->ucopy.dma_chan) {
-		struct sk_buff *skb;
 		dma_cookie_t done, used;
 
 		dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);

[PATCH 3/7] [I/OAT] Don't offload copies for loopback traffic

[Chris Leech]

Local traffic (loopback) is generally in cache anyway, and the overhead
cost of offloading the copy is worse than just doing it with the CPU.

Signed-off-by: Chris Leech <christopher.leech@intel.com>
---

 net/ipv4/tcp.c |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 36f6b64..7971e73 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -1107,6 +1107,7 @@ int tcp_recvmsg(struct kiocb *iocb, stru
 	int copied_early = 0;
 	int available = 0;
 	struct sk_buff *skb;
+	struct dst_entry *dst;
 
 	lock_sock(sk);
 
@@ -1136,7 +1137,8 @@ int tcp_recvmsg(struct kiocb *iocb, stru
 	skb = skb_peek_tail(&sk->sk_receive_queue);
 	if (skb)
 		available = TCP_SKB_CB(skb)->seq + skb->len - (*seq);
-	if ((available < target) &&
+	dst = __sk_dst_get(sk);
+	if ((available < target) && (!dst || (dst->dev != &loopback_dev)) &&
 	    (len > sysctl_tcp_dma_copybreak) && !(flags & MSG_PEEK) &&
 	    !sysctl_tcp_low_latency && __get_cpu_var(softnet_data).net_dma) {
 		preempt_enable_no_resched();

Re: [PATCH 3/7] [I/OAT] Don't offload copies for loopback traffic

[Andi Kleen]

> @@ -1136,7 +1137,8 @@ int tcp_recvmsg(struct kiocb *iocb, stru
>  	skb = skb_peek_tail(&sk->sk_receive_queue);
>  	if (skb)
>  		available = TCP_SKB_CB(skb)->seq + skb->len - (*seq);
> -	if ((available < target) &&
> +	dst = __sk_dst_get(sk);
> +	if ((available < target) && (!dst || (dst->dev != &loopback_dev)) &&

You just added another potential cache miss to a critical
path. A bit flag in the socket would be better.

But is it really worth this ugly special case?

-Andi

Re: [PATCH 3/7] [I/OAT] Don't offload copies for loopback traffic

[David Miller]

From: Andi Kleen <ak@suse.de>
Date: Fri, 18 Aug 2006 20:17:18 +0200

> 
> > @@ -1136,7 +1137,8 @@ int tcp_recvmsg(struct kiocb *iocb, stru
> >  	skb = skb_peek_tail(&sk->sk_receive_queue);
> >  	if (skb)
> >  		available = TCP_SKB_CB(skb)->seq + skb->len - (*seq);
> > -	if ((available < target) &&
> > +	dst = __sk_dst_get(sk);
> > +	if ((available < target) && (!dst || (dst->dev != &loopback_dev)) &&
> 
> You just added another potential cache miss to a critical
> path. A bit flag in the socket would be better.
> 
> But is it really worth this ugly special case?

I think it isn't.  It is really gross.

[PATCH 4/7] [I/OAT] Remove the wrappers around read(bwl)/write(bwl) in ioatdma

[Chris Leech]

Signed-off-by: Chris Leech <christopher.leech@intel.com>
---

 drivers/dma/ioatdma.c    |   60 +++++++++++------------
 drivers/dma/ioatdma_io.h |  118 ----------------------------------------------
 2 files changed, 28 insertions(+), 150 deletions(-)

diff --git a/drivers/dma/ioatdma.c b/drivers/dma/ioatdma.c
index be4fdd7..0be426f 100644
--- a/drivers/dma/ioatdma.c
+++ b/drivers/dma/ioatdma.c
@@ -32,7 +32,6 @@
 #include <linux/delay.h>
 #include <linux/dma-mapping.h>
 #include "ioatdma.h"
-#include "ioatdma_io.h"
 #include "ioatdma_registers.h"
 #include "ioatdma_hw.h"
 
@@ -51,8 +50,8 @@ static int enumerate_dma_channels(struct
 	int i;
 	struct ioat_dma_chan *ioat_chan;
 
-	device->common.chancnt = ioatdma_read8(device, IOAT_CHANCNT_OFFSET);
-	xfercap_scale = ioatdma_read8(device, IOAT_XFERCAP_OFFSET);
+	device->common.chancnt = readb(device->reg_base + IOAT_CHANCNT_OFFSET);
+	xfercap_scale = readb(device->reg_base + IOAT_XFERCAP_OFFSET);
 	xfercap = (xfercap_scale == 0 ? -1 : (1UL << xfercap_scale));
 
 	for (i = 0; i < device->common.chancnt; i++) {
@@ -123,7 +122,7 @@ static int ioat_dma_alloc_chan_resources
 	 * In-use bit automatically set by reading chanctrl
 	 * If 0, we got it, if 1, someone else did
 	 */
-	chanctrl = ioatdma_chan_read16(ioat_chan, IOAT_CHANCTRL_OFFSET);
+	chanctrl = readw(ioat_chan->reg_base + IOAT_CHANCTRL_OFFSET);
 	if (chanctrl & IOAT_CHANCTRL_CHANNEL_IN_USE)
 		return -EBUSY;
 
@@ -132,12 +131,12 @@ static int ioat_dma_alloc_chan_resources
 		IOAT_CHANCTRL_ERR_INT_EN |
 		IOAT_CHANCTRL_ANY_ERR_ABORT_EN |
 		IOAT_CHANCTRL_ERR_COMPLETION_EN;
-        ioatdma_chan_write16(ioat_chan, IOAT_CHANCTRL_OFFSET, chanctrl);
+        writew(chanctrl, ioat_chan->reg_base + IOAT_CHANCTRL_OFFSET);
 
-	chanerr = ioatdma_chan_read32(ioat_chan, IOAT_CHANERR_OFFSET);
+	chanerr = readl(ioat_chan->reg_base + IOAT_CHANERR_OFFSET);
 	if (chanerr) {
 		printk("IOAT: CHANERR = %x, clearing\n", chanerr);
-		ioatdma_chan_write32(ioat_chan, IOAT_CHANERR_OFFSET, chanerr);
+		writel(chanerr, ioat_chan->reg_base + IOAT_CHANERR_OFFSET);
 	}
 
 	/* Allocate descriptors */
@@ -161,10 +160,10 @@ static int ioat_dma_alloc_chan_resources
 		               &ioat_chan->completion_addr);
 	memset(ioat_chan->completion_virt, 0,
 	       sizeof(*ioat_chan->completion_virt));
-	ioatdma_chan_write32(ioat_chan, IOAT_CHANCMP_OFFSET_LOW,
-	               ((u64) ioat_chan->completion_addr) & 0x00000000FFFFFFFF);
-	ioatdma_chan_write32(ioat_chan, IOAT_CHANCMP_OFFSET_HIGH,
-	               ((u64) ioat_chan->completion_addr) >> 32);
+	writel(((u64) ioat_chan->completion_addr) & 0x00000000FFFFFFFF,
+	       ioat_chan->reg_base + IOAT_CHANCMP_OFFSET_LOW);
+	writel(((u64) ioat_chan->completion_addr) >> 32,
+	       ioat_chan->reg_base + IOAT_CHANCMP_OFFSET_HIGH);
 
 	ioat_start_null_desc(ioat_chan);
 	return i;
@@ -182,7 +181,7 @@ static void ioat_dma_free_chan_resources
 
 	ioat_dma_memcpy_cleanup(ioat_chan);
 
-	ioatdma_chan_write8(ioat_chan, IOAT_CHANCMD_OFFSET, IOAT_CHANCMD_RESET);
+	writeb(IOAT_CHANCMD_RESET, ioat_chan->reg_base + IOAT_CHANCMD_OFFSET);
 
 	spin_lock_bh(&ioat_chan->desc_lock);
 	list_for_each_entry_safe(desc, _desc, &ioat_chan->used_desc, node) {
@@ -210,9 +209,9 @@ static void ioat_dma_free_chan_resources
 	ioat_chan->last_completion = ioat_chan->completion_addr = 0;
 
 	/* Tell hw the chan is free */
-	chanctrl = ioatdma_chan_read16(ioat_chan, IOAT_CHANCTRL_OFFSET);
+	chanctrl = readw(ioat_chan->reg_base + IOAT_CHANCTRL_OFFSET);
 	chanctrl &= ~IOAT_CHANCTRL_CHANNEL_IN_USE;
-	ioatdma_chan_write16(ioat_chan, IOAT_CHANCTRL_OFFSET, chanctrl);
+	writew(chanctrl, ioat_chan->reg_base + IOAT_CHANCTRL_OFFSET);
 }
 
 /**
@@ -318,9 +317,8 @@ static dma_cookie_t do_ioat_dma_memcpy(s
 	spin_unlock_bh(&ioat_chan->desc_lock);
 
 	if (append)
-		ioatdma_chan_write8(ioat_chan,
-		                    IOAT_CHANCMD_OFFSET,
-		                    IOAT_CHANCMD_APPEND);
+		writeb(IOAT_CHANCMD_APPEND,
+		       ioat_chan->reg_base + IOAT_CHANCMD_OFFSET);
 	return cookie;
 }
 
@@ -417,9 +415,8 @@ static void ioat_dma_memcpy_issue_pendin
 
 	if (ioat_chan->pending != 0) {
 		ioat_chan->pending = 0;
-		ioatdma_chan_write8(ioat_chan,
-		                    IOAT_CHANCMD_OFFSET,
-		                    IOAT_CHANCMD_APPEND);
+		writeb(IOAT_CHANCMD_APPEND,
+		       ioat_chan->reg_base + IOAT_CHANCMD_OFFSET);
 	}
 }
 
@@ -449,7 +446,7 @@ static void ioat_dma_memcpy_cleanup(stru
 	if ((chan->completion_virt->full & IOAT_CHANSTS_DMA_TRANSFER_STATUS) ==
 		IOAT_CHANSTS_DMA_TRANSFER_STATUS_HALTED) {
 		printk("IOAT: Channel halted, chanerr = %x\n",
-			ioatdma_chan_read32(chan, IOAT_CHANERR_OFFSET));
+			readl(chan->reg_base + IOAT_CHANERR_OFFSET));
 
 		/* TODO do something to salvage the situation */
 	}
@@ -569,21 +566,21 @@ static irqreturn_t ioat_do_interrupt(int
 	unsigned long attnstatus;
 	u8 intrctrl;
 
-	intrctrl = ioatdma_read8(instance, IOAT_INTRCTRL_OFFSET);
+	intrctrl = readb(instance->reg_base + IOAT_INTRCTRL_OFFSET);
 
 	if (!(intrctrl & IOAT_INTRCTRL_MASTER_INT_EN))
 		return IRQ_NONE;
 
 	if (!(intrctrl & IOAT_INTRCTRL_INT_STATUS)) {
-		ioatdma_write8(instance, IOAT_INTRCTRL_OFFSET, intrctrl);
+		writeb(intrctrl, instance->reg_base + IOAT_INTRCTRL_OFFSET);
 		return IRQ_NONE;
 	}
 
-	attnstatus = ioatdma_read32(instance, IOAT_ATTNSTATUS_OFFSET);
+	attnstatus = readl(instance->reg_base + IOAT_ATTNSTATUS_OFFSET);
 
 	printk(KERN_ERR "ioatdma error: interrupt! status %lx\n", attnstatus);
 
-	ioatdma_write8(instance, IOAT_INTRCTRL_OFFSET, intrctrl);
+	writeb(intrctrl, instance->reg_base + IOAT_INTRCTRL_OFFSET);
 	return IRQ_HANDLED;
 }
 
@@ -612,14 +609,13 @@ static void ioat_start_null_desc(struct 
 	spin_unlock_bh(&ioat_chan->desc_lock);
 
 #if (BITS_PER_LONG == 64)
-	ioatdma_chan_write64(ioat_chan, IOAT_CHAINADDR_OFFSET, desc->phys);
+	writeq(desc->phys, ioat_chan->reg_base + IOAT_CHAINADDR_OFFSET);
 #else
-	ioatdma_chan_write32(ioat_chan,
-	                     IOAT_CHAINADDR_OFFSET_LOW,
-	                     (u32) desc->phys);
-	ioatdma_chan_write32(ioat_chan, IOAT_CHAINADDR_OFFSET_HIGH, 0);
+	writel((u32) desc->phys,
+	       ioat_chan->reg_base + IOAT_CHAINADDR_OFFSET_LOW);
+	writel(0, ioat_chan->reg_base + IOAT_CHAINADDR_OFFSET_HIGH);
 #endif
-	ioatdma_chan_write8(ioat_chan, IOAT_CHANCMD_OFFSET, IOAT_CHANCMD_START);
+	writeb(IOAT_CHANCMD_START, ioat_chan->reg_base + IOAT_CHANCMD_OFFSET);
 }
 
 /*
@@ -748,7 +744,7 @@ static int __devinit ioat_probe(struct p
 
 	device->reg_base = reg_base;
 
-	ioatdma_write8(device, IOAT_INTRCTRL_OFFSET, IOAT_INTRCTRL_MASTER_INT_EN);
+	writeb(IOAT_INTRCTRL_MASTER_INT_EN, device->reg_base + IOAT_INTRCTRL_OFFSET);
 	pci_set_master(pdev);
 
 	INIT_LIST_HEAD(&device->common.channels);
diff --git a/drivers/dma/ioatdma_io.h b/drivers/dma/ioatdma_io.h
deleted file mode 100644
index c0b4bf6..0000000
--- a/drivers/dma/ioatdma_io.h
+++ /dev/null
@@ -1,118 +0,0 @@
-/*
- * Copyright(c) 2004 - 2006 Intel Corporation. All rights reserved.
- *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License as published by the Free
- * Software Foundation; either version 2 of the License, or (at your option)
- * any later version.
- *
- * This program is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
- * more details.
- *
- * You should have received a copy of the GNU General Public License along with
- * this program; if not, write to the Free Software Foundation, Inc., 59
- * Temple Place - Suite 330, Boston, MA  02111-1307, USA.
- *
- * The full GNU General Public License is included in this distribution in the
- * file called COPYING.
- */
-#ifndef IOATDMA_IO_H
-#define IOATDMA_IO_H
-
-#include <asm/io.h>
-
-/*
- * device and per-channel MMIO register read and write functions
- * this is a lot of anoying inline functions, but it's typesafe
- */
-
-static inline u8 ioatdma_read8(struct ioat_device *device,
-                               unsigned int offset)
-{
-	return readb(device->reg_base + offset);
-}
-
-static inline u16 ioatdma_read16(struct ioat_device *device,
-                                 unsigned int offset)
-{
-	return readw(device->reg_base + offset);
-}
-
-static inline u32 ioatdma_read32(struct ioat_device *device,
-                                 unsigned int offset)
-{
-	return readl(device->reg_base + offset);
-}
-
-static inline void ioatdma_write8(struct ioat_device *device,
-                                  unsigned int offset, u8 value)
-{
-	writeb(value, device->reg_base + offset);
-}
-
-static inline void ioatdma_write16(struct ioat_device *device,
-                                   unsigned int offset, u16 value)
-{
-	writew(value, device->reg_base + offset);
-}
-
-static inline void ioatdma_write32(struct ioat_device *device,
-                                   unsigned int offset, u32 value)
-{
-	writel(value, device->reg_base + offset);
-}
-
-static inline u8 ioatdma_chan_read8(struct ioat_dma_chan *chan,
-                                    unsigned int offset)
-{
-	return readb(chan->reg_base + offset);
-}
-
-static inline u16 ioatdma_chan_read16(struct ioat_dma_chan *chan,
-                                      unsigned int offset)
-{
-	return readw(chan->reg_base + offset);
-}
-
-static inline u32 ioatdma_chan_read32(struct ioat_dma_chan *chan,
-                                      unsigned int offset)
-{
-	return readl(chan->reg_base + offset);
-}
-
-static inline void ioatdma_chan_write8(struct ioat_dma_chan *chan,
-                                       unsigned int offset, u8 value)
-{
-	writeb(value, chan->reg_base + offset);
-}
-
-static inline void ioatdma_chan_write16(struct ioat_dma_chan *chan,
-                                        unsigned int offset, u16 value)
-{
-	writew(value, chan->reg_base + offset);
-}
-
-static inline void ioatdma_chan_write32(struct ioat_dma_chan *chan,
-                                        unsigned int offset, u32 value)
-{
-	writel(value, chan->reg_base + offset);
-}
-
-#if (BITS_PER_LONG == 64)
-static inline u64 ioatdma_chan_read64(struct ioat_dma_chan *chan,
-                                      unsigned int offset)
-{
-	return readq(chan->reg_base + offset);
-}
-
-static inline void ioatdma_chan_write64(struct ioat_dma_chan *chan,
-                                        unsigned int offset, u64 value)
-{
-	writeq(value, chan->reg_base + offset);
-}
-#endif
-
-#endif /* IOATDMA_IO_H */
-

I/OAT configuration ?

[Ravinandan Arakali]

Hi,
I am trying to use I/OAT on one of the newer woodcrest boxes.
But not sure if things are configured properly since there
seems to be no change in performance with I/OAT enabled
or disabled.
Following are the steps followed.
1. MSI (CONFIG_PCI_MSI) is enabled in kernel(2.6.16.21).
2. In kernel DMA configuration, following are enabled.
     Support for DMA Engines
     Network: TCP receive copy offload
     Test DMA Client
     Intel I/OAT DMA support
3. I manually load the ioatdma driver (modprobe ioatdma)

As per some documentation I read, when step #3 is performed
successfully, directories dma0chanX is supposed to be created
under /sys/class/dma but in my case, this directory stays
empty. I don't see any messages in /var/log/messages.
Any idea what is missing ?

Thanks,
Ravi

[PATCH 5/7] [I/OAT] Remove the use of writeq from the ioatdma driver

[Chris Leech]

There's only one now anyway, and it's not in a performance path,
so make it behave the same on 32-bit and 64-bit CPUs.

Signed-off-by: Chris Leech <christopher.leech@intel.com>
---

 drivers/dma/ioatdma.c |   10 ++++------
 1 files changed, 4 insertions(+), 6 deletions(-)

diff --git a/drivers/dma/ioatdma.c b/drivers/dma/ioatdma.c
index 0be426f..d6d817c 100644
--- a/drivers/dma/ioatdma.c
+++ b/drivers/dma/ioatdma.c
@@ -608,13 +608,11 @@ static void ioat_start_null_desc(struct 
 	list_add_tail(&desc->node, &ioat_chan->used_desc);
 	spin_unlock_bh(&ioat_chan->desc_lock);
 
-#if (BITS_PER_LONG == 64)
-	writeq(desc->phys, ioat_chan->reg_base + IOAT_CHAINADDR_OFFSET);
-#else
-	writel((u32) desc->phys,
+	writel(((u64) desc->phys) & 0x00000000FFFFFFFF,
 	       ioat_chan->reg_base + IOAT_CHAINADDR_OFFSET_LOW);
-	writel(0, ioat_chan->reg_base + IOAT_CHAINADDR_OFFSET_HIGH);
-#endif
+	writel(((u64) desc->phys) >> 32,
+	       ioat_chan->reg_base + IOAT_CHAINADDR_OFFSET_HIGH);
+
 	writeb(IOAT_CHANCMD_START, ioat_chan->reg_base + IOAT_CHANCMD_OFFSET);
 }
 

[PATCH 6/7] [I/OAT] Add documentation for the tcp_dma_copybreak sysctl

[Chris Leech]

Signed-off-by: Chris Leech <christopher.leech@intel.com>
---

 Documentation/networking/ip-sysctl.txt |    6 ++++++
 1 files changed, 6 insertions(+), 0 deletions(-)

diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt
index d46338a..841d61e 100644
--- a/Documentation/networking/ip-sysctl.txt
+++ b/Documentation/networking/ip-sysctl.txt
@@ -369,6 +369,12 @@ tcp_slow_start_after_idle - BOOLEAN
 	be timed out after an idle period.
 	Default: 1
 
+tcp_dma_copybreak - INTEGER
+	Lower limit, in bytes, of the size of socket reads that will be
+	offloaded to a DMA copy engine, if one is present in the system
+	and CONFIG_NET_DMA is enabled.
+	Default: 4096
+
 IP Variables:
 
 ip_local_port_range - 2 INTEGERS

[PATCH 7/7] [I/OAT] Add entries to MAINTAINERS for the DMA memcpy subsystem and ioatdma

[Chris Leech]

Signed-off-by: Chris Leech <christopher.leech@intel.com>
---

 MAINTAINERS |   10 ++++++++++
 1 files changed, 10 insertions(+), 0 deletions(-)

diff --git a/MAINTAINERS b/MAINTAINERS
index 21116cc..9ae73c9 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -881,6 +881,11 @@ M:	tori@unhappy.mine.nu
 L:	linux-kernel@vger.kernel.org
 S:	Maintained
 
+DMA GENERIC MEMCPY SUBSYSTEM
+P:	Chris Leech
+M:	christopher.leech@intel.com
+S:	Maintained
+
 DOCBOOK FOR DOCUMENTATION
 P:	Martin Waitz
 M:	tali@admingilde.org
@@ -1469,6 +1474,11 @@ P:	Tigran Aivazian
 M:	tigran@veritas.com
 S:	Maintained
 
+INTEL I/OAT DMA DRIVER
+P:	Chris Leech
+M:	christopher.leech@intel.com
+S:	Supported
+
 INTEL IXP4XX RANDOM NUMBER GENERATOR SUPPORT
 P:	Deepak Saxena
 M:	dsaxena@plexity.net

Re: [PATCH 7/7] [I/OAT] Add entries to MAINTAINERS for the DMA memcpy subsystem and ioatdma

[Randy.Dunlap]

On Tue, 15 Aug 2006, Chris Leech wrote:

> Signed-off-by: Chris Leech <christopher.leech@intel.com>
> ---
>
>  MAINTAINERS |   10 ++++++++++
>  1 files changed, 10 insertions(+), 0 deletions(-)
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 21116cc..9ae73c9 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -881,6 +881,11 @@ M:	tori@unhappy.mine.nu
>  L:	linux-kernel@vger.kernel.org
>  S:	Maintained
>
> +DMA GENERIC MEMCPY SUBSYSTEM
> +P:	Chris Leech
> +M:	christopher.leech@intel.com
> +S:	Maintained
> +
>  DOCBOOK FOR DOCUMENTATION
>  P:	Martin Waitz
>  M:	tali@admingilde.org
> @@ -1469,6 +1474,11 @@ P:	Tigran Aivazian
>  M:	tigran@veritas.com
>  S:	Maintained
>
> +INTEL I/OAT DMA DRIVER
> +P:	Chris Leech
> +M:	christopher.leech@intel.com
> +S:	Supported
> +
>  INTEL IXP4XX RANDOM NUMBER GENERATOR SUPPORT
>  P:	Deepak Saxena
>  M:	dsaxena@plexity.net

Can you also add an appropriate mailing list for these,
such as netdev or lkml etc.?

Thanks,
-- 
~Randy

[PATCH 7/7 v2] [I/OAT] Add entries to MAINTAINERS for the DMA memcpy subsystem and ioatdma

[Chris Leech]

Signed-off-by: Chris Leech <christopher.leech@intel.com>
---

 MAINTAINERS |   12 ++++++++++++
 1 files changed, 12 insertions(+), 0 deletions(-)

diff --git a/MAINTAINERS b/MAINTAINERS
index 21116cc..2d484aa 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -881,6 +881,12 @@ M:	tori@unhappy.mine.nu
 L:	linux-kernel@vger.kernel.org
 S:	Maintained
 
+DMA GENERIC MEMCPY SUBSYSTEM
+P:	Chris Leech
+M:	christopher.leech@intel.com
+L:	linux-kernel@vger.kernel.org
+S:	Maintained
+
 DOCBOOK FOR DOCUMENTATION
 P:	Martin Waitz
 M:	tali@admingilde.org
@@ -1469,6 +1475,12 @@ P:	Tigran Aivazian
 M:	tigran@veritas.com
 S:	Maintained
 
+INTEL I/OAT DMA DRIVER
+P:	Chris Leech
+M:	christopher.leech@intel.com
+L:	linux-kernel@vger.kernel.org
+S:	Supported
+
 INTEL IXP4XX RANDOM NUMBER GENERATOR SUPPORT
 P:	Deepak Saxena
 M:	dsaxena@plexity.net

Re: [PATCH 1/7] [I/OAT] Push pending transactions to hardware more frequently

[Pavel Machek]

Hi!

> Every 20 descriptors turns out to be to few append commands with
> newer/faster CPUs.  Pushing every 4 still cuts down on MMIO writes to an
> acceptable level without letting the DMA engine run out of work.
> 
> Signed-off-by: Chris Leech <christopher.leech@intel.com>
> ---
> 
>  drivers/dma/ioatdma.c |    4 ++--
>  1 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/dma/ioatdma.c b/drivers/dma/ioatdma.c
> index dbd4d6c..be4fdd7 100644
> --- a/drivers/dma/ioatdma.c
> +++ b/drivers/dma/ioatdma.c
> @@ -310,7 +310,7 @@ static dma_cookie_t do_ioat_dma_memcpy(s
>  	list_splice_init(&new_chain, ioat_chan->used_desc.prev);
>  
>  	ioat_chan->pending += desc_count;
> -	if (ioat_chan->pending >= 20) {
> +	if (ioat_chan->pending >= 4) {
>  		append = 1;
>  		ioat_chan->pending = 0;
>  	}
> @@ -818,7 +818,7 @@ static void __devexit ioat_remove(struct
>  }
>  
>  /* MODULE API */
> -MODULE_VERSION("1.7");
> +MODULE_VERSION("1.9");
>  MODULE_LICENSE("GPL");
>  MODULE_AUTHOR("Intel Corporation");

Huh, two version bumps for... ONE ONE-LINER :-).

Could we get rid of embedded version? It helps no one.

-- 
Thanks for all the (sleeping) penguins.

Re: [PATCH 1/7] [I/OAT] Push pending transactions to hardware more frequently

[Chris Leech]

On 8/18/06, Pavel Machek <pavel@ucw.cz> wrote:
>
> Huh, two version bumps for... ONE ONE-LINER :-).
>
> Could we get rid of embedded version? It helps no one.

Version numbers for drivers that can be built as modules are very
helpful for anyone wanting to upgrade a driver on top of a
distribution supported kernel.  If you always just use the latest
kernel source, you're right it doesn't help you.  But that's not
everyone.

This one skips two versions because I'm trying to sync up a 1.8
version tested internally with the 1.7+ upstream changes that's in the
kernel now.

I'll accept that the official policy is to not version modules when
MODULE_VERSION is removed :-)

- Chris

[PATCH 0/7] drivers/dma & I/OAT fixes

[Chris Leech]

Various fixes for the hardware memcpy engine code and ioatdma

Most of these I've posted before, except for the patch to handle sysfs
errors from Jeff Garzik.  I've dropped the controversial change to not
offload loopback traffic.

These changes can be pulled from
	git://lost.foo-projects.org/~cleech/linux-2.6 master

--
Chris Leech <christopher.leech@intel.com>
I/O Acceleration Technology Software Development
LAN Access Division / Digital Enterprise Group 

[PATCH 1/7] I/OAT: Push pending transactions to hardware more frequently

[Chris Leech]

Every 20 descriptors turns out to be to few append commands with
newer/faster CPUs.  Pushing every 4 still cuts down on MMIO writes to an
acceptable level without letting the DMA engine run out of work.

Signed-off-by: Chris Leech <christopher.leech@intel.com>
---

 drivers/dma/ioatdma.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/dma/ioatdma.c b/drivers/dma/ioatdma.c
index 0358419..f3b34b5 100644
--- a/drivers/dma/ioatdma.c
+++ b/drivers/dma/ioatdma.c
@@ -310,7 +310,7 @@ static dma_cookie_t do_ioat_dma_memcpy(s
 	list_splice_init(&new_chain, ioat_chan->used_desc.prev);
 
 	ioat_chan->pending += desc_count;
-	if (ioat_chan->pending >= 20) {
+	if (ioat_chan->pending >= 4) {
 		append = 1;
 		ioat_chan->pending = 0;
 	}
@@ -818,7 +818,7 @@ static void __devexit ioat_remove(struct
 }
 
 /* MODULE API */
-MODULE_VERSION("1.7");
+MODULE_VERSION("1.9");
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Intel Corporation");