godot: High CPU usage, time spent in texture updating

Godot version:

Any Godot 3.1 alpha

OS/device including version:

Issue description:

I’m using Godot in a project where a lot of sprites are packed into a spritesheet and many .tres files generated and then used for creating TextureAtlases. All went well until today I noticed the IDE became highly unresponsive. Activity Monitor shows 100% CPU usage. I investigated a bit and found out most time it’s doing this:

thread #1, queue = 'com.apple.main-thread', stop reason = signal SIGSTOP
    frame #0: 0x00000001029d096a godot.osx.tools.64`PoolVector<unsigned char>::resize(int) [inlined] operator new(p_size=1, p_pointer=0x000000017c1ab6ba, check=1, p_description="") at memory.h:104
    frame #1: 0x00000001029d0966 godot.osx.tools.64`PoolVector<unsigned char>::resize(this=0x00007fff5fbfe118, p_size=134217728) at dvector.h:589
  * frame #2: 0x0000000100c5d7cf godot.osx.tools.64`RasterizerStorageGLES3::texture_get_data(this=0x0000000108060a10, p_texture=RID @ 0x00007fff5fbfe170, p_layer=0) const at rasterizer_storage_gles3.cpp:1054
    frame #3: 0x00000001027d447b godot.osx.tools.64`VisualServerRaster::texture_get_data(this=0x0000000106b38990, arg1=RID @ 0x00007fff5fbfe1b8, arg2=0) const at visual_server_raster.h:153
    frame #4: 0x000000010282fa5b godot.osx.tools.64`CommandQueueMT::CommandRet2<VisualServer, Ref<Image> (VisualServer::*)(RID, int) const, RID, int, Ref<Image> >::call(this=0x00000001124e5570) at command_queue_mt.h:307
    frame #5: 0x000000010282d987 godot.osx.tools.64`CommandQueueMT::flush_one(this=0x00000001124c5128, p_lock=false) at command_queue_mt.h:425
    frame #6: 0x0000000102815b64 godot.osx.tools.64`CommandQueueMT::flush_all(this=0x00000001124c5128) at command_queue_mt.h:465
    frame #7: 0x0000000102815c0f godot.osx.tools.64`VisualServerWrapMT::sync(this=0x00000001124c5010) at visual_server_wrap_mt.cpp:90
    frame #8: 0x00000001000497fd godot.osx.tools.64`Main::iteration() at main.cpp:1867
    frame #9: 0x000000010000fd7e godot.osx.tools.64`OS_OSX::run(this=0x00007fff5fbfe640) at os_osx.mm:2564
    frame #10: 0x0000000100017698 godot.osx.tools.64`main(argc=4, argv=0x00007fff5fbff998) at godot_main_osx.mm:100
    frame #11: 0x00007fffcace9235 libdyld.dylib`start + 1
    frame #12: 0x00007fffcace9235 libdyld.dylib`start + 1

So, basically it reallocates the memory for the large texture (6MB) all the time, thus the CPU usage:

frame #2: 0x0000000100c5d7cf godot.osx.tools.64`RasterizerStorageGLES3::texture_get_data(this=0x0000000108060a10, p_texture=RID @ 0x00007fff5fbfe170, p_layer=0) const at rasterizer_storage_gles3.cpp:1054
   1051	
   1052		int data_size = Image::get_image_data_size(texture->alloc_width, texture->alloc_height, real_format, texture->mipmaps > 1);
   1053	
-> 1054		data.resize(data_size * 2); //add some memory at the end, just in case for buggy drivers
   1055		PoolVector<uint8_t>::Write wb = data.write();
   1056	
   1057		glActiveTexture(GL_TEXTURE0);

Deleting the texture from the project helps. I’m not sure what is causing this.

Steps to reproduce:

Minimal reproduction project: