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Re: [PATCH] Call target_can_download_tracepoint if there are tracepoints to download
- From: Yao Qi <qiyaoltc at gmail dot com>
- To: Pedro Alves <palves at redhat dot com>
- Cc: Yao Qi <qiyaoltc at gmail dot com>, gdb-patches at sourceware dot org
- Date: Thu, 10 Sep 2015 12:35:12 +0100
- Subject: Re: [PATCH] Call target_can_download_tracepoint if there are tracepoints to download
- Authentication-results: sourceware.org; auth=none
- References: <1441721612-15314-1-git-send-email-yao dot qi at linaro dot org> <55F00C91 dot 2000602 at redhat dot com>
Pedro Alves <palves@redhat.com> writes:
> I'd suggest moving tribool in common/common-types.h. It's just
> be a matter of time before we want to use this in gdbserver too..
Yes, of course. Patch below is what I pushed in.
--
Yao (éå)
From dd2e65cc2c48f2fe1343840b610bc6dd4246f35b Mon Sep 17 00:00:00 2001
From: Yao Qi <yao.qi@linaro.org>
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 <yao.qi@linaro.org>
* 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.
diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 85d8bc2..ba521c0 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,12 @@
+2015-09-10 Yao Qi <yao.qi@linaro.org>
+
+ * 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 <palves@redhat.com>
* inf-loop.c (inferior_event_handler): Delete INF_TIMER case.
diff --git a/gdb/breakpoint.c b/gdb/breakpoint.c
index 4709de7..520793a 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 55b41ab..3f60a9a 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 81b3ded..f7b45f7 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). */