From 22138db609721897c213e5a08ccaca206c0fb1f6 Mon Sep 17 00:00:00 2001 From: Tom Tromey Date: Sat, 16 Mar 2019 14:36:57 -0600 Subject: [PATCH] Add maint set/show worker-threads This adds maint commands to control the number of worker threads that gdb can use. 2019-11-26 Tom Tromey * NEWS: Add entry. * maint.c (_initialize_maint_cmds): Add "worker-threads" maint commands. Call update_thread_pool_size. (update_thread_pool_size, maintenance_set_worker_threads): New functions. (n_worker_threads): New global. gdb/doc/ChangeLog 2019-11-26 Tom Tromey * gdb.texinfo (Maintenance Commands): Document new maint commands. Change-Id: I4fb514faa05879d8afe62c77036a4469d57dca2a --- gdb/ChangeLog | 9 +++++++++ gdb/NEWS | 7 +++++++ gdb/doc/ChangeLog | 5 +++++ gdb/doc/gdb.texinfo | 15 +++++++++++++++ gdb/maint.c | 41 +++++++++++++++++++++++++++++++++++++++++ 5 files changed, 77 insertions(+) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index b73ae8dd813..289cbce640b 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,12 @@ +2019-11-26 Tom Tromey + + * NEWS: Add entry. + * maint.c (_initialize_maint_cmds): Add "worker-threads" maint + commands. Call update_thread_pool_size. + (update_thread_pool_size, maintenance_set_worker_threads): New + functions. + (n_worker_threads): New global. + 2019-11-26 Christian Biesinger Tom Tromey diff --git a/gdb/NEWS b/gdb/NEWS index 01b38cf9bd8..5fd0f413181 100644 --- a/gdb/NEWS +++ b/gdb/NEWS @@ -149,6 +149,13 @@ set style highlight background COLOR set style highlight intensity VALUE Control the styling of highlightings. +maint set worker-threads +maint show worker-threads + Control the number of worker threads that can be used by GDB. The + default is "unlimited", which lets GDB choose a number that is + reasonable. Currently worker threads are only used when demangling + the names of linker symbols. + maint set test-settings KIND maint show test-settings KIND A set of commands used by the testsuite for exercising the settings diff --git a/gdb/doc/ChangeLog b/gdb/doc/ChangeLog index c6fa5f573ea..06d7a6d27ff 100644 --- a/gdb/doc/ChangeLog +++ b/gdb/doc/ChangeLog @@ -1,3 +1,8 @@ +2019-11-26 Tom Tromey + + * gdb.texinfo (Maintenance Commands): Document new maint + commands. + 2019-11-25 Luis Machado * gdb.texinfo (Debugging Output): Document set debug diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo index 18bb18b2245..e3be0cdf015 100644 --- a/gdb/doc/gdb.texinfo +++ b/gdb/doc/gdb.texinfo @@ -37876,6 +37876,21 @@ with the DWARF frame unwinders enabled. If DWARF frame unwinders are not supported for a particular target architecture, then enabling this flag does not cause them to be used. + +@kindex maint set worker-threads +@kindex maint show worker-threads +@item maint set worker-threads +@item maint show worker-threads +Control the number of worker threads that may be used by @value{GDBN}. +On capable hosts, @value{GDBN} may use multiple threads to speed up +certain CPU-intensive operations, such as demangling symbol names. +While the number of threads used by @value{GDBN} may vary, this +command can be used to set an upper bound on this number. The default +is @code{unlimited}, which lets @value{GDBN} choose a reasonable +number. Note that this only controls worker threads started by +@value{GDBN} itself; libraries used by @value{GDBN} may start threads +of their own. + @kindex maint set profile @kindex maint show profile @cindex profiling GDB diff --git a/gdb/maint.c b/gdb/maint.c index ce59ef6cca4..7ab3fdb64c1 100644 --- a/gdb/maint.c +++ b/gdb/maint.c @@ -46,6 +46,10 @@ #include "cli/cli-setshow.h" #include "cli/cli-cmds.h" +#if CXX_STD_THREAD +#include "gdbsupport/thread-pool.h" +#endif + static void maintenance_do_deprecate (const char *, int); /* Access the maintenance subcommands. */ @@ -840,6 +844,30 @@ maintenance_set_profile_cmd (const char *args, int from_tty, error (_("Profiling support is not available on this system.")); } #endif + +static int n_worker_threads = -1; + +/* Update the thread pool for the desired number of threads. */ +static void +update_thread_pool_size () +{ +#if CXX_STD_THREAD + int n_threads = n_worker_threads; + + if (n_threads < 0) + n_threads = std::thread::hardware_concurrency (); + + gdb::thread_pool::g_thread_pool->set_thread_count (n_threads); +#endif +} + +static void +maintenance_set_worker_threads (const char *args, int from_tty, + struct cmd_list_element *c) +{ + update_thread_pool_size (); +} + /* If true, display time usage both at startup and for each command. */ @@ -1313,4 +1341,17 @@ When enabled GDB is profiled."), show_maintenance_profile_p, &maintenance_set_cmdlist, &maintenance_show_cmdlist); + + add_setshow_zuinteger_unlimited_cmd ("worker-threads", + class_maintenance, + &n_worker_threads, _("\ +Set the number of worker threads GDB can use."), _("\ +Show the number of worker threads GDB can use."), _("\ +GDB may use multiple threads to speed up certain CPU-intensive operations,\n\ +such as demangling symbol names."), + maintenance_set_worker_threads, NULL, + &maintenance_set_cmdlist, + &maintenance_show_cmdlist); + + update_thread_pool_size (); } -- 2.30.2