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Don Breazeal 09c98b448f Optimize memory_xfer_partial for remote
Some analysis we did here showed that increasing the cap on the
transfer size in target.c:memory_xfer_partial could give 20% or more
improvement in remote load across JTAG.  Transfer sizes were capped
to 4K bytes because of performance problems encountered with the
restore command, documented here:

https://sourceware.org/ml/gdb-patches/2013-07/msg00611.html

and in commit 67c059c29e ("Improve performance of large restore
commands").

The 4K cap was introduced because in a case where the restore command
requested a 100MB transfer, memory_xfer_partial would repeatedy
allocate and copy an entire 100MB buffer in order to properly handle
breakpoint shadow instructions, even though memory_xfer_partial would
actually only write a small portion of the buffer contents.

A couple of alternative solutions were suggested:
* change the algorithm for handling the breakpoint shadow instructions
* throttle the transfer size up or down based on the previous actual
  transfer size

I tried implementing the throttling approach, and my implementation
reduced the performance in some cases.

This patch implements a new target function that returns that target's
limit on memory transfer size.  It defaults to ULONGEST_MAX bytes,
because for native targets there is no marshaling and thus no limit is
needed.  For remote targets it uses get_memory_write_packet_size.

gdb/ChangeLog:

	* remote.c (remote_get_memory_xfer_limit): New function.
	* target-delegates.c: Regenerate.
	* target.c (memory_xfer_partial): Call
	target_ops.to_get_memory_xfer_limit.
	* target.h (struct target_ops)
	<to_get_memory_xfer_limit>: New member.
2016-07-01 11:13:48 -07:00
bfd Fix Thumb-2 BL detection 2016-07-01 16:13:25 +01:00
binutils Fix potential buffer overflows with sprintf and very large integer values. 2016-07-01 12:35:01 +01:00
config
cpu
elfcpp Add support for MIPS .rld_map section. 2016-06-20 12:16:26 -07:00
etc Fix compile time warning messages building with gcc v6.1.1 2016-06-13 10:49:26 +01:00
gas [AArch64] Fix +nofp16 handling 2016-07-01 16:50:59 +01:00
gdb Optimize memory_xfer_partial for remote 2016-07-01 11:13:48 -07:00
gold Fix gold testsuite failure with GCC 6. 2016-06-29 23:24:35 -07:00
gprof
include [AArch64] Fix +nofp16 handling 2016-07-01 16:50:59 +01:00
intl
ld Fix Thumb-2 BL detection 2016-07-01 16:13:25 +01:00
libdecnumber
libiberty Don't needlessly clear xmemdup allocated memory. 2016-05-31 20:34:47 +09:30
opcodes x86: allow suffix-less movzw and 64-bit movzb 2016-07-01 09:01:41 +02:00
readline
sim Add support for simulating big-endian AArch64 binaries. 2016-06-30 09:10:41 +01:00
texinfo
zlib
.cvsignore
.gitattributes
.gitignore
ChangeLog [TILEPro] Don't build gdb 2016-06-28 14:16:15 -04:00
compile
config-ml.in
config.guess Fix typo introduced during the most recent synchronization update. 2016-05-27 14:34:06 +01:00
config.rpath
config.sub
configure [TILEPro] Don't build gdb 2016-06-28 14:16:15 -04:00
configure.ac [TILEPro] Don't build gdb 2016-06-28 14:16:15 -04:00
COPYING
COPYING.LIB
COPYING.LIBGLOSS
COPYING.NEWLIB
COPYING3
COPYING3.LIB
depcomp
djunpack.bat
install-sh
libtool.m4
ltgcc.m4
ltmain.sh
ltoptions.m4
ltsugar.m4
ltversion.m4
lt~obsolete.m4
MAINTAINERS
Makefile.def
Makefile.in Add dependencies to configure rule 2016-05-28 22:36:04 +09:30
Makefile.tpl Add dependencies to configure rule 2016-05-28 22:36:04 +09:30
makefile.vms
missing
mkdep
mkinstalldirs
move-if-change
README
README-maintainer-mode
setup.com
src-release.sh
symlink-tree
ylwrap

		   README for GNU development tools

This directory contains various GNU compilers, assemblers, linkers, 
debuggers, etc., plus their support routines, definitions, and documentation.

If you are receiving this as part of a GDB release, see the file gdb/README.
If with a binutils release, see binutils/README;  if with a libg++ release,
see libg++/README, etc.  That'll give you info about this
package -- supported targets, how to use it, how to report bugs, etc.

It is now possible to automatically configure and build a variety of
tools with one command.  To build all of the tools contained herein,
run the ``configure'' script here, e.g.:

	./configure 
	make

To install them (by default in /usr/local/bin, /usr/local/lib, etc),
then do:
	make install

(If the configure script can't determine your type of computer, give it
the name as an argument, for instance ``./configure sun4''.  You can
use the script ``config.sub'' to test whether a name is recognized; if
it is, config.sub translates it to a triplet specifying CPU, vendor,
and OS.)

If you have more than one compiler on your system, it is often best to
explicitly set CC in the environment before running configure, and to
also set CC when running make.  For example (assuming sh/bash/ksh):

	CC=gcc ./configure
	make

A similar example using csh:

	setenv CC gcc
	./configure
	make

Much of the code and documentation enclosed is copyright by
the Free Software Foundation, Inc.  See the file COPYING or
COPYING.LIB in the various directories, for a description of the
GNU General Public License terms under which you can copy the files.

REPORTING BUGS: Again, see gdb/README, binutils/README, etc., for info
on where and how to report problems.