From: Bartosz Szczepanek <b...@semihalf.com>
Hi,
When dealing with low network speed during tftp, the analysis showed
two issues - UEFI tftp and network stack spend a lot of time (~3.5ms,
comparing to U-Boot's ~0.6ms) on preparing ACK packet after receiving
data block from host. The network driver itself is using SNP and its
time spent on executing SnpTransmit routine is negligible, so it is
definitely not a problem.
This patch however is only releated to above mentioned problem. It
occurred that despite our MTU is set to 1500, each block of data has
to be split to 512 chunks, so the very long receive/ack sequence was
executed three times more than needed.
Below is an example of a solution of increasing TFTP block size
to maximum allowed by 1500 MTU. The default block size is changed,
as well as this option is negotiatied with host. For sure a situation,
when proposed, increased block size is rejected by host (a default
fall back to 512 should happen) should be handled properly.
Also a dynamic dependency between port's MTU was considered, but there
are two problems - how to pass it to Mtftp4 module and way of negotiating
size with host - option requires string format. Hence IMO it's better
to stick to arbitrary size.
I would be very grateful for any comments and ideas, how to handle
this issue properly.
Best reards,
Marcin
---
MdeModulePkg/Universal/Network/Mtftp4Dxe/Mtftp4Impl.h | 2 +-
ShellPkg/Library/UefiShellTftpCommandLib/Tftp.c | 5 +++++
2 files changed, 6 insertions(+), 1 deletion(-)
diff --git a/MdeModulePkg/Universal/Network/Mtftp4Dxe/Mtftp4Impl.h
b/MdeModulePkg/Universal/Network/Mtftp4Dxe/Mtftp4Impl.h
index 527fd1d..9a2d409 100644
--- a/MdeModulePkg/Universal/Network/Mtftp4Dxe/Mtftp4Impl.h
+++ b/MdeModulePkg/Universal/Network/Mtftp4Dxe/Mtftp4Impl.h
@@ -55,7 +55,7 @@ typedef struct _MTFTP4_PROTOCOL MTFTP4_PROTOCOL;
#define MTFTP4_DEFAULT_SERVER_PORT 69
#define MTFTP4_DEFAULT_TIMEOUT 3
#define MTFTP4_DEFAULT_RETRY 5
-#define MTFTP4_DEFAULT_BLKSIZE 512
+#define MTFTP4_DEFAULT_BLKSIZE 1468
#define MTFTP4_TIME_TO_GETMAP 5
#define MTFTP4_STATE_UNCONFIGED 0
diff --git a/ShellPkg/Library/UefiShellTftpCommandLib/Tftp.c
b/ShellPkg/Library/UefiShellTftpCommandLib/Tftp.c
index 831b9c3..3e06b67 100644
--- a/ShellPkg/Library/UefiShellTftpCommandLib/Tftp.c
+++ b/ShellPkg/Library/UefiShellTftpCommandLib/Tftp.c
@@ -894,12 +894,17 @@ DownloadFile (
TftpContext->DownloadedNbOfBytes = 0;
TftpContext->LastReportedNbOfBytes = 0;
+ UINT8 name[] = "blksize";
+ UINT8 val[] = "1468";
+ EFI_MTFTP4_OPTION Blksize = { name, val };
ZeroMem (&Mtftp4Token, sizeof (EFI_MTFTP4_TOKEN));
Mtftp4Token.Filename = (UINT8*)AsciiFilePath;
Mtftp4Token.BufferSize = FileSize;
Mtftp4Token.Buffer = Buffer;
Mtftp4Token.CheckPacket = CheckPacket;
Mtftp4Token.Context = (VOID*)TftpContext;
+ Mtftp4Token.OptionCount = 1;
+ Mtftp4Token.OptionList = &Blksize;
ShellPrintHiiEx (
-1, -1, NULL, STRING_TOKEN (STR_TFTP_DOWNLOADING),
--
1.8.3.1
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