Re: [PATCH 10/11] gdb: maintain ptid -> thread map, optimize find_thread_ptid

[Pedro Alves <pedro@palves.net>]

On 2021-06-22 5:57 p.m., Simon Marchi via Gdb-patches wrote:
> When debugging a large number of threads (thousands), looking up a
> thread by ptid_t using the inferior::thread_list linked list can add up.
> 
> Add inferior::thread_map, an std::unordered_map indexed by ptid_t, and
> change the find_thread_ptid function to look up a thread using
> std::unordered_map::find, instead of iterating on all of the
> inferior's threads.  This should make it faster to look up a thread
> from its ptid.
> 
> gdb/ChangeLog:
> yyyy-mm-dd  Simon Marchi  <simon.marchi@efficios.com>
>       	    Pedro Alves  <palves@palves.net>
> 
> 	* gdbarch-selftests.c (register_to_value_test): Update the mock
> 	inferior's thread map as well.
> 	* inferior.c (inferior::clear_thread_list): Clear the thread map.
> 	* inferior.h: Include <unordered_map>.
> 	(class inferior::thread_map): New field.
> 	* regcache.c (cooked_read_test): Update the mock inferior's thread
> 	map as well.
> 	* thread.c (set_thread_exited): Remove the thread from the thread
> 	map.
> 	(new_thread): Insert the thread in the ptid map.
> 	(find_thread_ptid): Lookup up the thread in the ptid map.
> 	(thread_change_ptid): Update ptid map entry.
> 

( Should this have Co-Authored-By: ? )

OK.

> Change-Id: I3a8da0a839e18dee5bb98b8b7dbeb7f3dfa8ae1c
> ---