From dd2e65cc2c48f2fe1343840b610bc6dd4246f35b Mon Sep 17 00:00:00 2001 From: Yao Qi Date: Thu, 10 Sep 2015 12:31:36 +0100 Subject: [PATCH] Call target_can_download_tracepoint if there are tracepoints to download Nowadays, GDB calls target_can_download_tracepoint at the entry of download_tracepoint_locations, which is called by. update_global_location_list. Sometimes, it is not needed to call target_can_download_tracepoint at all because there is no tracepoint created. In remote target, target_can_download_tracepoint send qTStatus to the remote in order to know whether tracepoint can be downloaded or not. This means some redundant qTStatus packets are sent. This patch is to teach GDB to call target_can_download_tracepoint lazily, only on the moment there are tracepoint to download. gdb.perf/single-step.exp (with a local patch to measure RSP packets) shows the number of RSP packets is reduced because there is no tracepoint at all, so GDB doesn't send qTStatus any more. # of RSP packets original patched single-step rsp 1000 7000 6000 single-step rsp 2000 14000 12000 single-step rsp 3000 21000 18000 single-step rsp 4000 28000 24000 gdb: 2015-09-10 Yao Qi * breakpoint.c (download_tracepoint_locations): New local can_download_tracepoint. Check the result of target_can_download_tracepoint and save it in can_download_tracepoint if there are tracepoints to download. * linux-nat.h (enum tribool): Move it to ... * common/common-types.h: ... here. --- gdb/ChangeLog | 9 +++++++++ gdb/breakpoint.c | 15 ++++++++++++--- gdb/common/common-types.h | 2 ++ gdb/linux-nat.h | 1 - 4 files changed, 23 insertions(+), 4 deletions(-) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 85d8bc20ebe..ba521c078c2 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,12 @@ +2015-09-10 Yao Qi + + * breakpoint.c (download_tracepoint_locations): New local + can_download_tracepoint. Check the result of + target_can_download_tracepoint and save it in + can_download_tracepoint if there are tracepoints to download. + * linux-nat.h (enum tribool): Move it to ... + * common/common-types.h: ... here. + 2015-09-09 Pedro Alves * inf-loop.c (inferior_event_handler): Delete INF_TIMER case. diff --git a/gdb/breakpoint.c b/gdb/breakpoint.c index 4709de72faf..520793a72e1 100644 --- a/gdb/breakpoint.c +++ b/gdb/breakpoint.c @@ -12146,9 +12146,7 @@ download_tracepoint_locations (void) { struct breakpoint *b; struct cleanup *old_chain; - - if (!target_can_download_tracepoint ()) - return; + enum tribool can_download_tracepoint = TRIBOOL_UNKNOWN; old_chain = save_current_space_and_thread (); @@ -12163,6 +12161,17 @@ download_tracepoint_locations (void) : !may_insert_tracepoints)) continue; + if (can_download_tracepoint == TRIBOOL_UNKNOWN) + { + if (target_can_download_tracepoint ()) + can_download_tracepoint = TRIBOOL_TRUE; + else + can_download_tracepoint = TRIBOOL_FALSE; + } + + if (can_download_tracepoint == TRIBOOL_FALSE) + break; + for (bl = b->loc; bl; bl = bl->next) { /* In tracepoint, locations are _never_ duplicated, so diff --git a/gdb/common/common-types.h b/gdb/common/common-types.h index 55b41abb8fc..3f60a9a9a56 100644 --- a/gdb/common/common-types.h +++ b/gdb/common/common-types.h @@ -58,4 +58,6 @@ typedef unsigned long long ULONGEST; /* * The largest CORE_ADDR value. */ #define CORE_ADDR_MAX (~ (CORE_ADDR) 0) +enum tribool { TRIBOOL_UNKNOWN = -1, TRIBOOL_FALSE = 0, TRIBOOL_TRUE = 1 }; + #endif /* COMMON_TYPES_H */ diff --git a/gdb/linux-nat.h b/gdb/linux-nat.h index 81b3ded2b01..f7b45f7bc69 100644 --- a/gdb/linux-nat.h +++ b/gdb/linux-nat.h @@ -116,7 +116,6 @@ struct lwp_info extern struct lwp_info *lwp_list; /* Does the current host support PTRACE_GETREGSET? */ -enum tribool { TRIBOOL_UNKNOWN = -1, TRIBOOL_FALSE = 0, TRIBOOL_TRUE = 1 }; extern enum tribool have_ptrace_getregset; /* Iterate over each active thread (light-weight process). */ -- 2.30.2