From: Tom de Vries <tdevries@suse.de>
To: Tom Tromey <tom@tromey.com>, gdb-patches@sourceware.org
Subject: Re: [PATCH v3 00/18] Index DWARF in the background
Date: Mon, 27 Nov 2023 16:31:38 +0100 [thread overview]
Message-ID: <ac4ca8f9-d680-442d-b005-be6ddf5ddec2@suse.de> (raw)
In-Reply-To: <20231122-t-bg-dwarf-reading-v3-0-fc3180de63c4@tromey.com>
On 11/23/23 06:32, Tom Tromey wrote:
> This series changes gdb to do its initial DWARF indexing in the
> background.
>
> This process is mostly asynchronous with respect to the rest of gdb.
> That is, rather than pre-emptively waiting for scanning to complete,
> now gdb's main thread will only wait when some result of the scan is
> required.
>
> This drastically improves gdb's apparent startup time in the "normal"
> case where a user does "gdb some-executable" -- e.g., for starting gdb
> on itself, the time until the prompt returns goes from ~1.2 seconds to
> ~0.06 seconds on my machine.
>
> This approach works by hiding most of the work from the user. Waiting
> can still be needed; for example if one starts gdb and immediately
> sets a breakpoint -- however, because the indexer is reasonably fast,
> and human reaction times are slow, this series still manages to be
> fairly successful.
>
> My current belief is that doing any better than this will probably
> require a new debug format that isn't quite so cursed to read.
>
> I regression tested this on x86-64 Fedora 38. I've also built it with
> TSAN and tested that, though TSAN seems to introduce random timeouts
> into the testsuite when I use "make -j8 check".
>
I've tested the series with target boards:
- unix
- cc-with-dwz
- cc-with-index-cache
and found no new issues.
I've also test-driven it a bit, indeed it makes gdb feel more
responsive, I think it's a nice improvement.
Thanks,
- Tom
> ---
> Changes in v3:
> - Rebase on top of the C++17 changes
> - Apply Tom de Vries' bug fix
> - Fix a "save gdb-index" bug found by Alexandra
> - Link to v2: https://inbox.sourceware.org/gdb-patches/20231112-t-bg-dwarf-reading-v2-0-70fb170012ba@tromey.com
>
> Changes in v2:
> - Updated to final style of BFD locking
> - Added a thread safety fix for DWO
> - Added a patch to pre-read DWZ sections
> - Added calls to bfd_thread_cleanup and bfd_cache_close
> - Link to v1: https://inbox.sourceware.org/gdb-patches/20231029173839.471514-1-tom@tromey.com
>
> ---
> Tom Tromey (18):
> Don't use objfile::intern in DWO code
> Pre-read DWZ section data
> Add a couple of bfd_cache_close calls
> Add thread-safety to gdb's BFD wrappers
> Refactor complaint thread-safety approach
> Add quick_symbol_functions::compute_main_name
> Add gdb::task_group
> Move cooked_index_storage to cooked-index.h
> Add "maint set dwarf synchronous"
> Change how cooked index waits for threads
> Do more DWARF reading in the background
> Simplify the public DWARF API
> Remove two quick_symbol_functions methods
> Change current_language to be a macro
> Lazy language setting
> Optimize lookup_minimal_symbol_text
> Avoid language-based lookups in startup path
> Back out some parallel_for_each features
>
> gdb/NEWS | 4 +
> gdb/breakpoint.c | 4 +-
> gdb/coffread.c | 6 +-
> gdb/complaints.c | 24 +-
> gdb/complaints.h | 37 +-
> gdb/defs.h | 2 +-
> gdb/doc/gdb.texinfo | 18 +
> gdb/dwarf2/cooked-index.c | 201 ++++---
> gdb/dwarf2/cooked-index.h | 316 ++++++++--
> gdb/dwarf2/dwz.c | 90 ++-
> gdb/dwarf2/dwz.h | 13 +-
> gdb/dwarf2/macro.c | 2 -
> gdb/dwarf2/public.h | 18 +-
> gdb/dwarf2/read.c | 729 +++++++++++++----------
> gdb/dwarf2/read.h | 2 +-
> gdb/elfread.c | 6 +-
> gdb/gdb_bfd.c | 58 ++
> gdb/gdb_bfd.h | 5 +
> gdb/gdbthread.h | 3 +-
> gdb/jit.c | 4 +-
> gdb/language.c | 51 +-
> gdb/language.h | 34 +-
> gdb/machoread.c | 11 +-
> gdb/main.c | 3 +-
> gdb/minsyms.c | 69 ++-
> gdb/objfile-flags.h | 4 -
> gdb/objfiles.h | 17 +-
> gdb/psymtab.c | 1 -
> gdb/quick-symbol.h | 17 +-
> gdb/symfile-debug.c | 77 +--
> gdb/symfile.c | 22 +-
> gdb/symtab.c | 2 +
> gdb/testsuite/gdb.dwarf2/dw2-error.exp | 1 +
> gdb/testsuite/gdb.dwarf2/dw2-missing-cu-tag.exp | 2 +
> gdb/testsuite/gdb.dwarf2/dw2-stack-boundary.exp | 2 +
> gdb/testsuite/gdb.dwarf2/dw2-using-debug-str.exp | 2 +
> gdb/testsuite/gdb.dwarf2/dw2-zero-range.exp | 4 +-
> gdb/testsuite/gdb.dwarf2/fission-reread.exp | 5 +-
> gdb/testsuite/gdb.dwarf2/no-gnu-debuglink.exp | 1 +
> gdb/testsuite/gdb.dwarf2/struct-with-sig-2.exp | 10 +-
> gdb/thread.c | 8 +-
> gdb/top.c | 2 +-
> gdb/unittests/parallel-for-selftests.c | 47 --
> gdb/xcoffread.c | 3 +-
> gdbsupport/Makefile.am | 1 +
> gdbsupport/Makefile.in | 6 +-
> gdbsupport/parallel-for.h | 234 +-------
> gdbsupport/task-group.cc | 97 +++
> gdbsupport/task-group.h | 64 ++
> 49 files changed, 1409 insertions(+), 930 deletions(-)
> ---
> base-commit: a54a99a6e5159e4406e172f074b3729b2135c28c
> change-id: 20231112-t-bg-dwarf-reading-00b65fa130b3
>
> Best regards,
next prev parent reply other threads:[~2023-11-27 15:31 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-23 5:32 Tom Tromey
2023-11-23 5:32 ` [PATCH v3 01/18] Don't use objfile::intern in DWO code Tom Tromey
2023-11-23 5:32 ` [PATCH v3 02/18] Pre-read DWZ section data Tom Tromey
2023-11-23 5:32 ` [PATCH v3 03/18] Add a couple of bfd_cache_close calls Tom Tromey
2023-11-23 5:32 ` [PATCH v3 04/18] Add thread-safety to gdb's BFD wrappers Tom Tromey
2023-11-23 5:32 ` [PATCH v3 05/18] Refactor complaint thread-safety approach Tom Tromey
2023-11-23 5:32 ` [PATCH v3 06/18] Add quick_symbol_functions::compute_main_name Tom Tromey
2023-11-23 5:32 ` [PATCH v3 07/18] Add gdb::task_group Tom Tromey
2023-11-23 5:32 ` [PATCH v3 08/18] Move cooked_index_storage to cooked-index.h Tom Tromey
2023-11-23 5:32 ` [PATCH v3 09/18] Add "maint set dwarf synchronous" Tom Tromey
2023-11-23 7:02 ` Eli Zaretskii
2023-11-23 5:32 ` [PATCH v3 10/18] Change how cooked index waits for threads Tom Tromey
2023-11-23 5:32 ` [PATCH v3 11/18] Do more DWARF reading in the background Tom Tromey
2023-11-23 5:32 ` [PATCH v3 12/18] Simplify the public DWARF API Tom Tromey
2023-11-23 5:32 ` [PATCH v3 13/18] Remove two quick_symbol_functions methods Tom Tromey
2023-11-23 5:32 ` [PATCH v3 14/18] Change current_language to be a macro Tom Tromey
2023-11-23 5:32 ` [PATCH v3 15/18] Lazy language setting Tom Tromey
2023-11-23 5:32 ` [PATCH v3 16/18] Optimize lookup_minimal_symbol_text Tom Tromey
2023-11-23 5:32 ` [PATCH v3 17/18] Avoid language-based lookups in startup path Tom Tromey
2023-11-23 5:32 ` [PATCH v3 18/18] Back out some parallel_for_each features Tom Tromey
2023-11-27 15:31 ` Tom de Vries [this message]
2023-12-10 17:19 ` [PATCH v3 00/18] Index DWARF in the background Tom Tromey
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