Hi Richard,

I've continued working on my USB EEM support, and just pushed my changes to https://github.com/bcran/edk2/tree/usb-net .

I was wondering when you think you might have the next set of patches ready for review?


Thanks.

Rebecca Cran


On 1/12/23 01:36, RichardHo [何明忠] via groups.io wrote:
Hi Michael,

We add this patch in my X86 platform and use the NCM device to test IPV4 PXE 
boot from 1330MB ISO file.

No this patch: 35 sec to download 1330M ISO file
Add this patch: 181  sec to download 1330M ISO file

The patch will increase boot time in my X86 platform.

Thanks,
Richard

-----Original Message-----
From: Michael Brown <mc...@ipxe.org>
Sent: 2023年1月10日 7:50 AM
To: devel@edk2.groups.io; tinhngu...@os.amperecomputing.com; Richard Ho (何明忠) 
<richar...@ami.com>
Subject: [EXTERNAL] Re: [edk2-devel] [PATCH 1/3] UsbNetworkPkg/UsbRndis: Add 
USB RNDIS devices support


**CAUTION: The e-mail below is from an external source. Please exercise caution 
before opening attachments, clicking links, or following guidance.**

On 08/01/2023 10:41, tinhnguyen via groups.io wrote:
The root cause is that we spend a long time waiting for USB
UsbBulkTransfer to complete, but if there is no data to communicate
-> it will always time out.
Coincidentally, I have just implemented a fix for this.  It works by 
implementing a simple credit-based rate limiter.  Calls to
UsbEthReceive() are limited to 10 per second while the receive datapath is 
idle.  No limiting takes place while the receive datapath is active.

I have tried to match the existing code style (i.e. zero explanatory comments).

Richard Ho: please consider using this rate limiting approach (or something 
very similar).

Patch inline below:

diff --git a/UsbNetworkPkg/Include/Protocol/EdkIIUsbEthernetProtocol.h
b/UsbNetworkPkg/Include/Protocol/EdkIIUsbEthernetProtocol.h
index df6ebc64ef..d0e2048114 100644
--- a/UsbNetworkPkg/Include/Protocol/EdkIIUsbEthernetProtocol.h
+++ b/UsbNetworkPkg/Include/Protocol/EdkIIUsbEthernetProtocol.h
@@ -160,6 +160,8 @@ typedef struct {
     UINT8                          CurrentNodeAddress[PXE_MAC_LENGTH];
     UINT8                          BroadcastNodeAddress[PXE_MAC_LENGTH];
     EFI_USB_DEVICE_REQUEST         Request;
+  EFI_EVENT                      RateLimiter;
+  UINTN                          RateLimitCredit;
   } NIC_DATA;

   #define NIC_DATA_SIGNATURE  SIGNATURE_32('n', 'i', 'c', 'd') diff --git 
a/UsbNetworkPkg/NetworkCommon/DriverBinding.h
b/UsbNetworkPkg/NetworkCommon/DriverBinding.h
index 946727ffc9..ae1d3c201e 100644
--- a/UsbNetworkPkg/NetworkCommon/DriverBinding.h
+++ b/UsbNetworkPkg/NetworkCommon/DriverBinding.h
@@ -25,6 +25,8 @@
   #define RX_BUFFER_COUNT                  32
   #define TX_BUFFER_COUNT                  32
   #define MEMORY_REQUIRE                   0
+#define RATE_LIMITER_INTERVAL            1000000  // 10Hz
+#define RATE_LIMITER_BURST               10

   #define UNDI_DEV_SIGNATURE  SIGNATURE_32('u','n','d','i')
   #define UNDI_DEV_FROM_THIS(a)  CR(a, NIC_DEVICE, NiiProtocol,
UNDI_DEV_SIGNATURE)
diff --git a/UsbNetworkPkg/NetworkCommon/PxeFunction.c
b/UsbNetworkPkg/NetworkCommon/PxeFunction.c
index fd53a215a4..2a9b4f6111 100644
--- a/UsbNetworkPkg/NetworkCommon/PxeFunction.c
+++ b/UsbNetworkPkg/NetworkCommon/PxeFunction.c
@@ -29,6 +29,21 @@ API_FUNC  gUndiApiTable[] = {
     UndiReceive
   };

+STATIC
+VOID
+EFIAPI
+UndiRateLimiterCallback (
+  IN  EFI_EVENT Event,
+  IN  VOID      *Context
+  )
+{
+  NIC_DATA *Nic = Context;
+
+  if (Nic->RateLimitCredit < RATE_LIMITER_BURST) {
+    Nic->RateLimitCredit++;
+  }
+}
+
   /**
     This command is used to determine the operational state of the UNDI.

@@ -100,9 +115,6 @@ UndiStart (
       Cdb->StatFlags = PXE_STATFLAGS_COMMAND_FAILED;
       Cdb->StatCode  = PXE_STATCODE_INVALID_CDB;
       return;
-  } else {
-    Cdb->StatFlags = PXE_STATFLAGS_COMMAND_COMPLETE;
-    Cdb->StatCode  = PXE_STATCODE_SUCCESS;
     }

     if (Nic->State != PXE_STATFLAGS_GET_STATE_STOPPED) { @@ -120,14 +132,46 @@ 
UndiStart (
     Nic->PxeStart.UnMap_Mem = 0;
     Nic->PxeStart.Sync_Mem  = Cpb->Sync_Mem;
     Nic->PxeStart.Unique_ID = Cpb->Unique_ID;
-  Nic->State              = PXE_STATFLAGS_GET_STATE_STARTED;
+
+  Status = gBS->CreateEvent (
+    EVT_TIMER | EVT_NOTIFY_SIGNAL,
+    TPL_CALLBACK,
+    UndiRateLimiterCallback,
+    Nic,
+    &Nic->RateLimiter
+    );
+  if (EFI_ERROR (Status)) {
+    goto ErrorCreateEvent;
+  }
+
+  Status = gBS->SetTimer (
+    Nic->RateLimiter,
+    TimerPeriodic,
+    RATE_LIMITER_INTERVAL
+    );
+  if (EFI_ERROR (Status)) {
+    goto ErrorSetTimer;
+  }

     if (Nic->UsbEth->UsbEthUndi.UsbEthUndiStart != NULL) {
       Status = Nic->UsbEth->UsbEthUndi.UsbEthUndiStart (Cdb, Nic);
       if (EFI_ERROR (Status)) {
-      Cdb->StatFlags = PXE_STATFLAGS_COMMAND_FAILED;
+      goto ErrorUndiStart;
       }
     }
+
+  Nic->State     = PXE_STATFLAGS_GET_STATE_STARTED;
+  Cdb->StatFlags = PXE_STATFLAGS_COMMAND_COMPLETE;  Cdb->StatCode  =
+ PXE_STATCODE_SUCCESS;  return;
+
+ ErrorUndiStart:
+  gBS->SetTimer (&Nic->RateLimiter, TimerCancel, 0);
+ ErrorSetTimer:
+  gBS->CloseEvent (&Nic->RateLimiter);
+ ErrorCreateEvent:
+  Cdb->StatFlags = PXE_STATFLAGS_COMMAND_FAILED;  Cdb->StatCode  =
+ PXE_STATCODE_DEVICE_FAILURE;
   }

   /**
@@ -183,6 +227,10 @@ UndiStop (
     Nic->PxeStart.Sync_Mem  = 0;
     Nic->State              = PXE_STATFLAGS_GET_STATE_STOPPED;

+  gBS->SetTimer (&Nic->RateLimiter, TimerCancel, 0);
+
+  gBS->CloseEvent (&Nic->RateLimiter);
+
     if (Nic->UsbEth->UsbEthUndi.UsbEthUndiStop != NULL) {
       Status = Nic->UsbEth->UsbEthUndi.UsbEthUndiStop (Cdb, Nic);
       if (EFI_ERROR (Status)) {
@@ -1506,8 +1554,13 @@ Receive (
     }

     while (1) {
+    if (Nic->RateLimitCredit == 0) {
+      break;
+    }
+
       Status = Nic->UsbEth->UsbEthReceive (Cdb, Nic->UsbEth, (VOID *)BulkInData, 
&DataLength);
       if (EFI_ERROR (Status)) {
+      Nic->RateLimitCredit--;
         break;
       }


Thanks,

Michael

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