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| author | Anton Blanchard <anton@samba.org> | 2013-11-04 21:39:20 +1100 |
|---|---|---|
| committer | Anton Blanchard <anton@samba.org> | 2013-11-04 22:18:23 +1100 |
| commit | 67c059c29e1fb0cdeacdd2005f955514d8d1fb34 (patch) | |
| tree | a8a6ca67ff1b3f4e311447e82c2d650086aac93c | |
| parent | 88b8e63904fda25c029deaf25d7b4e489b351470 (diff) | |
| download | gdb-67c059c29e1fb0cdeacdd2005f955514d8d1fb34.zip gdb-67c059c29e1fb0cdeacdd2005f955514d8d1fb34.tar.gz gdb-67c059c29e1fb0cdeacdd2005f955514d8d1fb34.tar.bz2 | |
Improve performance of large restore commands
I noticed a large (100MB) restore took hours to complete. The problem
is memory_xfer_partial repeatedly mallocs and memcpys the entire
100MB buffer for breakpoint shadow handling only to find a small
portion of it is actually written.
The testcase that originally took hours now takes 50 seconds.
gdb/
2013-07-29 Anton Blanchard <anton@samba.org>
* target.c (memory_xfer_partial): Cap write to 4KB.
| -rw-r--r-- | gdb/ChangeLog | 4 | ||||
| -rw-r--r-- | gdb/target.c | 7 |
2 files changed, 11 insertions, 0 deletions
diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 2d6a751..7d7a6fc 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,7 @@ +2013-11-04 Anton Blanchard <anton@samba.org> + + * target.c (memory_xfer_partial): Cap write to 4KB. + 2013-11-01 Tiago Stürmer Daitx <tdaitx@linux.vnet.ibm.com> * breakpoint.c (create_longjmp_master_breakpoint): Allow libc diff --git a/gdb/target.c b/gdb/target.c index 22d7fb6..7aeab79 100644 --- a/gdb/target.c +++ b/gdb/target.c @@ -1678,6 +1678,13 @@ memory_xfer_partial (struct target_ops *ops, enum target_object object, void *buf; struct cleanup *old_chain; + /* A large write request is likely to be partially satisfied + by memory_xfer_partial_1. We will continually malloc + and free a copy of the entire write request for breakpoint + shadow handling even though we only end up writing a small + subset of it. Cap writes to 4KB to mitigate this. */ + len = min (4096, len); + buf = xmalloc (len); old_chain = make_cleanup (xfree, buf); memcpy (buf, writebuf, len); |