russelltg created this revision.
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russelltg requested review of this revision.
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Herald added a subscriber: lldb-commits.
https://github.com/llvm/llvm-project/issues/62750
I setup a simple test with a large .so (~100MiB) that was only present on the
target machine
but not present on the local machine, and ran a lldb server on the target and
connectd to it.
LLDB properly downloads the file from the remote, but it does so at a very slow
speed, even over a hardwired 1Gbps connection!
Increasing the buffer size for downloading these helps quite a bit.
Test setup:
bash
$ cat gen.py
print('const char* hugeglobal = ')
for _ in range(1000*500):
print(' "' + '1234'*50 + '"')
print(';')
print('const char* mystring() { return hugeglobal; }')
$ gen.py > huge.c
$ mkdir libdir
$ gcc -fPIC huge.c -Wl,-soname,libhuge.so -o libdir/libhuge.so -shared
$ gcc test.c -L libdir -l huge -Wl,-rpath='$$ORIGIN' -o test
$ rsync libdir remote:~/
$ ssh remote bash -c "cd ~/libdir /llvm/buildr/bin/lldb-server platform
--server --listen '*:1234'"
in another terminal
bash
$ rm -rf ~/.lldb # clear cache
$ cat connect.lldb
platform select remote-linux
platform connect connect://10.0.0.14:1234
file test
b main
r
image list
c
q
$ time /llvm/buildr/bin/lldb --source connect.lldb
Times with various buffer sizes:
1kiB (current): ~22s
8kiB: ~8s
16kiB: ~4s
32kiB: ~3.5s
64kiB: ~2.8s
128kiB: ~2.6s
256kiB: ~2.1s
512kiB: ~2.1s
1MiB: ~2.1s
2MiB: ~2.1s
I choose 512kiB from this list as it seems to be the place where the returns
start diminishing and still isn't that much memory
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D153060
Files:
lldb/source/Target/Platform.cpp
Index: lldb/source/Target/Platform.cpp
===================================================================
--- lldb/source/Target/Platform.cpp
+++ lldb/source/Target/Platform.cpp
@@ -1630,7 +1630,7 @@
return error;
}
- std::vector<char> buffer(1024);
+ std::vector<char> buffer(512 * 1024);
auto offset = src_offset;
uint64_t total_bytes_read = 0;
while (total_bytes_read < src_size) {
Index: lldb/source/Target/Platform.cpp
===================================================================
--- lldb/source/Target/Platform.cpp
+++ lldb/source/Target/Platform.cpp
@@ -1630,7 +1630,7 @@
return error;
}
- std::vector<char> buffer(1024);
+ std::vector<char> buffer(512 * 1024);
auto offset = src_offset;
uint64_t total_bytes_read = 0;
while (total_bytes_read < src_size) {
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