From 50a0ffaf75e9d2d97200b523f2c600f40e9756b1 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Bj=C3=B8rn=20Mork?= Date: Sun, 11 May 2014 10:47:15 +0200 Subject: net: cdc_ncm/cdc_mbim: rework probing of NCM/MBIM functions MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The NCM class match in the cdc_mbim driver is confusing and cause unexpected behaviour. The USB core guarantees that a USB interface is in altsetting 0 when probing starts. This means that devices implementing a NCM 1.0 backwards compatible MBIM function (a "NCM/MBIM function") always hit the NCM entry in the cdc_mbim driver match table. Such functions will never match any of the MBIM entries. This causes unexpeced behaviour for cases where the NCM and MBIM entries are differet, which is currently the case for all except Ericsson devices. Improve the probing of NCM/MBIM functions by looking up the device again in the cdc_mbim match table after switching to the MBIM identity. The shared altsetting selection is updated to better accommodate the new probing logic, returning the preferred altsetting for the control interface instead of the data interface. The control interface altsetting update is moved to the cdc_mbim driver. It is never necessary to change the control interface altsetting for NCM. Cc: Greg Suarez Reported by: Yu-an Shih Signed-off-by: Bjørn Mork Signed-off-by: David S. Miller --- include/linux/usb/cdc_ncm.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux/usb') diff --git a/include/linux/usb/cdc_ncm.h b/include/linux/usb/cdc_ncm.h index 44b38b92236a..55b6feead93b 100644 --- a/include/linux/usb/cdc_ncm.h +++ b/include/linux/usb/cdc_ncm.h @@ -121,7 +121,7 @@ struct cdc_ncm_ctx { u16 connected; }; -u8 cdc_ncm_select_altsetting(struct usbnet *dev, struct usb_interface *intf); +u8 cdc_ncm_select_altsetting(struct usb_interface *intf); int cdc_ncm_bind_common(struct usbnet *dev, struct usb_interface *intf, u8 data_altsetting); void cdc_ncm_unbind(struct usbnet *dev, struct usb_interface *intf); struct sk_buff *cdc_ncm_fill_tx_frame(struct usbnet *dev, struct sk_buff *skb, __le32 sign); -- cgit v1.2.3 From 6c4e548ff36672eeb78f8288a2920d66fa4a6a66 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Bj=C3=B8rn=20Mork?= Date: Fri, 16 May 2014 21:48:22 +0200 Subject: net: cdc_ncm: use ethtool to tune coalescing settings MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Datagram coalescing is an integral part of the NCM and MBIM protocols, intended to reduce the interrupt load primarily on the device end of the USB link. As with all coalescing solutions, there is a trade-off between buffering and interrupts. The current defaults are based on the assumption that device side buffers should be the limiting factor. However, many modern high speed LTE modems suffers from buffer-bloat, making this assumption fail. This results in sub-optimal performance due to excessive coalescing. And in cases where such modems are connected to cheap embedded hosts there is often severe buffer allocation issues, giving very noticeable performance degradation . A start on improving this is going from build time hard coded limits to per device user configurable limits. The ethtool coalescing API was selected as user interface because, although the tuned values are buffer sizes, these settings directly control datagram coalescing. Signed-off-by: Bjørn Mork Signed-off-by: David S. Miller --- include/linux/usb/cdc_ncm.h | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'include/linux/usb') diff --git a/include/linux/usb/cdc_ncm.h b/include/linux/usb/cdc_ncm.h index 55b6feead93b..5c1066b4dc41 100644 --- a/include/linux/usb/cdc_ncm.h +++ b/include/linux/usb/cdc_ncm.h @@ -72,7 +72,9 @@ /* Restart the timer, if amount of datagrams is less than given value */ #define CDC_NCM_RESTART_TIMER_DATAGRAM_CNT 3 #define CDC_NCM_TIMER_PENDING_CNT 2 -#define CDC_NCM_TIMER_INTERVAL (400UL * NSEC_PER_USEC) +#define CDC_NCM_TIMER_INTERVAL_USEC 400UL +#define CDC_NCM_TIMER_INTERVAL_MIN 5UL +#define CDC_NCM_TIMER_INTERVAL_MAX (15UL * USEC_PER_SEC) /* The following macro defines the minimum header space */ #define CDC_NCM_MIN_HDR_SIZE \ @@ -107,6 +109,8 @@ struct cdc_ncm_ctx { spinlock_t mtx; atomic_t stop; + u64 timer_interval; + u32 tx_timer_pending; u32 tx_curr_frame_num; u32 rx_max; -- cgit v1.2.3 From 70559b8970e52aa9962dc823fd4498af06809544 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Bj=C3=B8rn=20Mork?= Date: Fri, 16 May 2014 21:48:23 +0200 Subject: net: cdc_ncm: use true max dgram count for header estimates MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Many newer NCM and MBIM devices will request a maximum tx datagram count which is much smaller than our hard-coded absolute max. We can reduce the overhead without sacrificing any of the simplicity for these devices, by simply using the true negotiated count in when calculated the maximum NTH and NDP header sizes. Signed-off-by: Bjørn Mork Signed-off-by: David S. Miller --- include/linux/usb/cdc_ncm.h | 10 +--------- 1 file changed, 1 insertion(+), 9 deletions(-) (limited to 'include/linux/usb') diff --git a/include/linux/usb/cdc_ncm.h b/include/linux/usb/cdc_ncm.h index 5c1066b4dc41..60a44b8a464e 100644 --- a/include/linux/usb/cdc_ncm.h +++ b/include/linux/usb/cdc_ncm.h @@ -76,15 +76,6 @@ #define CDC_NCM_TIMER_INTERVAL_MIN 5UL #define CDC_NCM_TIMER_INTERVAL_MAX (15UL * USEC_PER_SEC) -/* The following macro defines the minimum header space */ -#define CDC_NCM_MIN_HDR_SIZE \ - (sizeof(struct usb_cdc_ncm_nth16) + sizeof(struct usb_cdc_ncm_ndp16) + \ - (CDC_NCM_DPT_DATAGRAMS_MAX + 1) * sizeof(struct usb_cdc_ncm_dpe16)) - -#define CDC_NCM_NDP_SIZE \ - (sizeof(struct usb_cdc_ncm_ndp16) + \ - (CDC_NCM_DPT_DATAGRAMS_MAX + 1) * sizeof(struct usb_cdc_ncm_dpe16)) - #define cdc_ncm_comm_intf_is_mbim(x) ((x)->desc.bInterfaceSubClass == USB_CDC_SUBCLASS_MBIM && \ (x)->desc.bInterfaceProtocol == USB_CDC_PROTO_NONE) #define cdc_ncm_data_intf_is_mbim(x) ((x)->desc.bInterfaceProtocol == USB_CDC_MBIM_PROTO_NTB) @@ -110,6 +101,7 @@ struct cdc_ncm_ctx { atomic_t stop; u64 timer_interval; + u32 max_ndp_size; u32 tx_timer_pending; u32 tx_curr_frame_num; -- cgit v1.2.3 From 43e4c6dfc0fd781e68f20caf563a06f5c6ece995 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Bj=C3=B8rn=20Mork?= Date: Fri, 16 May 2014 21:48:24 +0200 Subject: net: cdc_ncm: set reasonable padding limits MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit We pad frames larger than X to maximum size for devices which don't need a ZLP after maximum sized frames. This allows the device to optimize its transfers for one fixed buffer size. X was arbitrarily set at 512 bytes regardless of real buffer maximum, causing extreme overheads due to excessive padding of larger tx buffers. Limit the padding to at most 3 full USB packets, still allowing the overhead to payload ratio of 3/1. Signed-off-by: Bjørn Mork Signed-off-by: David S. Miller --- include/linux/usb/cdc_ncm.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/usb') diff --git a/include/linux/usb/cdc_ncm.h b/include/linux/usb/cdc_ncm.h index 60a44b8a464e..79de6724d398 100644 --- a/include/linux/usb/cdc_ncm.h +++ b/include/linux/usb/cdc_ncm.h @@ -115,6 +115,7 @@ struct cdc_ncm_ctx { u16 tx_seq; u16 rx_seq; u16 connected; + u16 min_tx_pkt; }; u8 cdc_ncm_select_altsetting(struct usb_interface *intf); -- cgit v1.2.3 From beeecd42c3b41d17d0bf1d839db99274c287f514 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Bj=C3=B8rn=20Mork?= Date: Fri, 16 May 2014 21:48:25 +0200 Subject: net: cdc_ncm/cdc_mbim: adding NCM protocol statistics MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit To have an idea of the effects of the protocol coalescing it's useful to have some counters showing the different aspects. Due to the asymmetrical usbnet interface the netdev rx_bytes counter has been counting real received payload, while the tx_bytes counter has included the NCM/MBIM framing overhead. This overhead can be many times the payload because of the aggressive padding strategy of this driver, and will vary a lot depending on device and traffic. With very few exceptions, users are only interested in the payload size. Having an somewhat accurate payload byte counter is particularly important for mobile broadband devices, which many NCM devices and of course all MBIM devices are. Users and userspace applications will use this counter to monitor account quotas. Having protocol specific counters for the overhead, we are now able to correct the tx_bytes netdev counter so that it shows the real payload Signed-off-by: Bjørn Mork Signed-off-by: David S. Miller --- include/linux/usb/cdc_ncm.h | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'include/linux/usb') diff --git a/include/linux/usb/cdc_ncm.h b/include/linux/usb/cdc_ncm.h index 79de6724d398..88d2d7f1820f 100644 --- a/include/linux/usb/cdc_ncm.h +++ b/include/linux/usb/cdc_ncm.h @@ -116,6 +116,17 @@ struct cdc_ncm_ctx { u16 rx_seq; u16 connected; u16 min_tx_pkt; + + /* statistics */ + u32 tx_curr_frame_payload; + u32 tx_reason_ntb_full; + u32 tx_reason_ndp_full; + u32 tx_reason_timeout; + u32 tx_reason_max_datagram; + u64 tx_overhead; + u64 tx_ntbs; + u64 rx_overhead; + u64 rx_ntbs; }; u8 cdc_ncm_select_altsetting(struct usb_interface *intf); -- cgit v1.2.3 From 50f1cb1cc8f50fa88dbeaf990ae2bae91b9ff306 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Bj=C3=B8rn=20Mork?= Date: Fri, 16 May 2014 21:48:26 +0200 Subject: net: cdc_ncm: use sane defaults for rx/tx buffers MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Lots of devices request much larger buffers than reasonable. This cause real problems for users of hosts with limited resources. Reducing the default buffer size to 16kB for such devices is a reasonable trade-off between allowing them to aggregate traffic and avoiding memory exhaustion on resource restrained hosts. Signed-off-by: Bjørn Mork Signed-off-by: David S. Miller --- include/linux/usb/cdc_ncm.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'include/linux/usb') diff --git a/include/linux/usb/cdc_ncm.h b/include/linux/usb/cdc_ncm.h index 88d2d7f1820f..cde506731c48 100644 --- a/include/linux/usb/cdc_ncm.h +++ b/include/linux/usb/cdc_ncm.h @@ -52,6 +52,10 @@ #define CDC_NCM_NTB_MAX_SIZE_TX 32768 /* bytes */ #define CDC_NCM_NTB_MAX_SIZE_RX 32768 /* bytes */ +/* Initial NTB length */ +#define CDC_NCM_NTB_DEF_SIZE_TX 16384 /* bytes */ +#define CDC_NCM_NTB_DEF_SIZE_RX 16384 /* bytes */ + /* Minimum value for MaxDatagramSize, ch. 6.2.9 */ #define CDC_NCM_MIN_DATAGRAM_SIZE 1514 /* bytes */ -- cgit v1.2.3 From fa83dbeee55865678025b6c1637ca08860209f87 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Bj=C3=B8rn=20Mork?= Date: Fri, 16 May 2014 21:48:28 +0200 Subject: net: cdc_ncm: remove redundant "disconnected" flag MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Calling netif_carrier_{on,off} is sufficient. There is no need to duplicate the carrier state in a driver specific flag. Acked-by: Enrico Mioso Signed-off-by: Bjørn Mork Signed-off-by: David S. Miller --- include/linux/usb/cdc_ncm.h | 1 - 1 file changed, 1 deletion(-) (limited to 'include/linux/usb') diff --git a/include/linux/usb/cdc_ncm.h b/include/linux/usb/cdc_ncm.h index cde506731c48..8c5e38819828 100644 --- a/include/linux/usb/cdc_ncm.h +++ b/include/linux/usb/cdc_ncm.h @@ -118,7 +118,6 @@ struct cdc_ncm_ctx { u16 tx_ndp_modulus; u16 tx_seq; u16 rx_seq; - u16 connected; u16 min_tx_pkt; /* statistics */ -- cgit v1.2.3 From 7d10d2610cc02d432168ca0c5d964cd9e85c1b06 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Bj=C3=B8rn=20Mork?= Date: Mon, 19 May 2014 09:21:09 +0200 Subject: net: cdc_ncm: fix 64bit division build error MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The upper timer_interval limit is arbitrary and much higher than anything usable in the real world. Reducing it from 15s to ~4s to make the timer_interval fit in an u32 does not make much difference. The limit is still outside the practical bounds. This eliminates the need for a 64bit timer_interval, fixing a build error related to 64bit division: drivers/built-in.o: In function `cdc_ncm_get_coalesce': ak8975.c:(.text+0x1ac994): undefined reference to `__aeabi_uldivmod' Reported-by: Stephen Rothwell Signed-off-by: Bjørn Mork Signed-off-by: David S. Miller --- include/linux/usb/cdc_ncm.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'include/linux/usb') diff --git a/include/linux/usb/cdc_ncm.h b/include/linux/usb/cdc_ncm.h index 8c5e38819828..7c9b484735c5 100644 --- a/include/linux/usb/cdc_ncm.h +++ b/include/linux/usb/cdc_ncm.h @@ -78,7 +78,7 @@ #define CDC_NCM_TIMER_PENDING_CNT 2 #define CDC_NCM_TIMER_INTERVAL_USEC 400UL #define CDC_NCM_TIMER_INTERVAL_MIN 5UL -#define CDC_NCM_TIMER_INTERVAL_MAX (15UL * USEC_PER_SEC) +#define CDC_NCM_TIMER_INTERVAL_MAX (U32_MAX / NSEC_PER_USEC) #define cdc_ncm_comm_intf_is_mbim(x) ((x)->desc.bInterfaceSubClass == USB_CDC_SUBCLASS_MBIM && \ (x)->desc.bInterfaceProtocol == USB_CDC_PROTO_NONE) @@ -104,7 +104,7 @@ struct cdc_ncm_ctx { spinlock_t mtx; atomic_t stop; - u64 timer_interval; + u32 timer_interval; u32 max_ndp_size; u32 tx_timer_pending; -- cgit v1.2.3