From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 4809 invoked by alias); 19 Jul 2011 18:28:44 -0000 Received: (qmail 4798 invoked by uid 22791); 19 Jul 2011 18:28:43 -0000 X-SWARE-Spam-Status: No, hits=-1.7 required=5.0 tests=AWL,BAYES_00,KAM_STOCKGEN,RP_MATCHES_RCVD X-Spam-Check-By: sourceware.org Received: from mail.codesourcery.com (HELO mail.codesourcery.com) (38.113.113.100) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Tue, 19 Jul 2011 18:28:26 +0000 Received: (qmail 23618 invoked from network); 19 Jul 2011 18:28:26 -0000 Received: from unknown (HELO scottsdale.localnet) (pedro@127.0.0.2) by mail.codesourcery.com with ESMTPA; 19 Jul 2011 18:28:26 -0000 From: Pedro Alves To: gdb-patches@sourceware.org Subject: Re: [RFC][patch] Allow user to disable tracepoint support in gdbserver via command line Date: Tue, 19 Jul 2011 18:44:00 -0000 User-Agent: KMail/1.13.6 (Linux/2.6.38-8-generic; KDE/4.6.2; x86_64; ; ) Cc: Paul Pluzhnikov References: <20110719174427.D9BC3190BC8@elbrus2.mtv.corp.google.com> In-Reply-To: <20110719174427.D9BC3190BC8@elbrus2.mtv.corp.google.com> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-15" Content-Transfer-Encoding: 7bit Message-Id: <201107191928.23553.pedro@codesourcery.com> X-IsSubscribed: yes Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org X-SW-Source: 2011-07/txt/msg00489.txt.bz2 On Tuesday 19 July 2011 18:44:27, Paul Pluzhnikov wrote: > Greetings, > > Following up on my earlier "slow on high-latency links" message: > http://sourceware.org/ml/gdb-patches/2011-07/msg00391.html ... > > Another source of major slowness for me is the gdbserver querying for > tracepoint symbols. > > I see repeated (for each SOLIB) sequences of: > > 00:00:44 Sending packet: $qSymbol::#5b...Packet received: qSymbol:6764625f6167656e745f6764625f74705f686561705f627566666572 > 00:00:44 Packet qSymbol (symbol-lookup) is supported > 00:00:44 Sending packet: $qSymbol::6764625f6167656e745f6764625f74705f686561705f627566666572#1e...Packet received: qSymbol:6764625f6167656e745f6764625f6a756d705f7061645f627566666572 > 00:00:44 Sending packet: $qSymbol::6764625f6167656e745f6764625f6a756d705f7061645f627566666572#e1...Packet received: qSymbol:6764625f6167656e745f6764625f6a756d705f7061645f6275666665725f656e64 > 00:00:44 Sending packet: $qSymbol::6764625f6167656e745f6764625f6a756d705f7061645f6275666665725f656e64#ec...Packet received: qSymbol:6764625f6167656e745f636f6c6c656374696e67 > 00:00:44 Sending packet: $qSymbol::6764625f6167656e745f636f6c6c656374696e67#02...Packet received: qSymbol:6764625f6167656e745f6764625f636f6c6c656374 > 00:00:45 Sending packet: $qSymbol::6764625f6167656e745f6764625f636f6c6c656374#65...Packet received: qSymbol:6764625f6167656e745f73746f705f74726163696e67 > 00:00:45 Sending packet: $qSymbol::6764625f6167656e745f73746f705f74726163696e67#a3...Packet received: qSymbol:6764625f6167656e745f666c7573685f74726163655f627566666572 > 00:00:45 Sending packet: $qSymbol::6764625f6167656e745f666c7573685f74726163655f627566666572#23...Packet received: qSymbol:6764625f6167656e745f61626f75745f746f5f726571756573745f6275666665725f7370616365 > 00:00:45 Sending packet: $qSymbol::6764625f6167656e745f61626f75745f746f5f726571756573745f6275666665725f7370616365#3e...Packet received: qSymbol:6764625f6167656e745f74726163655f6275666665725f69735f66756c6c > 00:00:45 Sending packet: $qSymbol::6764625f6167656e745f74726163655f6275666665725f69735f66756c6c#58...Packet received: qSymbol:6764625f6167656e745f73746f7070696e675f7472616365706f696e74 > 00:00:45 Sending packet: $qSymbol::6764625f6167656e745f73746f7070696e675f7472616365706f696e74#ed...Packet received: qSymbol:6764625f6167656e745f657870725f6576616c5f726573756c74 > 00:00:46 Sending packet: $qSymbol::6764625f6167656e745f657870725f6576616c5f726573756c74#7b...Packet received: qSymbol:6764625f6167656e745f6572726f725f7472616365706f696e74 > 00:00:46 Sending packet: $qSymbol::6764625f6167656e745f6572726f725f7472616365706f696e74#79...Packet received: qSymbol:6764625f6167656e745f7472616365706f696e7473 > 00:00:46 Sending packet: $qSymbol::6764625f6167656e745f7472616365706f696e7473#06...Packet received: qSymbol:6764625f6167656e745f74726163696e67 > 00:00:46 Sending packet: $qSymbol::6764625f6167656e745f74726163696e67#30...Packet received: qSymbol:6764625f6167656e745f74726163655f6275666665725f6374726c > 00:00:46 Sending packet: $qSymbol::6764625f6167656e745f74726163655f6275666665725f6374726c#b0...Packet received: qSymbol:6764625f6167656e745f74726163655f6275666665725f6374726c5f63757272 > 00:00:46 Sending packet: $qSymbol::6764625f6167656e745f74726163655f6275666665725f6374726c5f63757272#f2...Packet received: qSymbol:6764625f6167656e745f74726163655f6275666665725f6c6f > 00:00:47 Sending packet: $qSymbol::6764625f6167656e745f74726163655f6275666665725f6c6f#0f...Packet received: qSymbol:6764625f6167656e745f74726163655f6275666665725f6869 > 00:00:47 Sending packet: $qSymbol::6764625f6167656e745f74726163655f6275666665725f6869#b7...Packet received: qSymbol:6764625f6167656e745f74726163656672616d655f726561645f636f756e74 > 00:00:47 Sending packet: $qSymbol::6764625f6167656e745f74726163656672616d655f726561645f636f756e74#b7...Packet received: qSymbol:6764625f6167656e745f74726163656672616d655f77726974655f636f756e74 > 00:00:47 Sending packet: $qSymbol::6764625f6167656e745f74726163656672616d655f77726974655f636f756e74#2e...Packet received: qSymbol:6764625f6167656e745f74726163656672616d65735f63726561746564 > 00:00:47 Sending packet: $qSymbol::6764625f6167656e745f74726163656672616d65735f63726561746564#4e...Packet received: qSymbol:6764625f6167656e745f74726163655f73746174655f7661726961626c6573 > 00:00:47 Sending packet: $qSymbol::6764625f6167656e745f74726163655f73746174655f7661726961626c6573#55...Packet received: qSymbol:6764625f6167656e745f6765745f7261775f726567 > 00:00:48 Sending packet: $qSymbol::6764625f6167656e745f6765745f7261775f726567#0d...Packet received: qSymbol:6764625f6167656e745f6765745f74726163655f73746174655f7661726961626c655f76616c7565 > 00:00:48 Sending packet: $qSymbol::6764625f6167656e745f6765745f74726163655f73746174655f7661726961626c655f76616c7565#a8...Packet received: qSymbol:6764625f6167656e745f7365745f74726163655f73746174655f7661726961626c655f76616c7565 > 00:00:48 Sending packet: $qSymbol::6764625f6167656e745f7365745f74726163655f73746174655f7661726961626c655f76616c7565#a5...Packet received: qSymbol:6764625f6167656e745f7573745f6c6f61646564 > 00:00:48 Sending packet: $qSymbol::6764625f6167656e745f7573745f6c6f61646564#cc...Packet received: qSymbol:6764625f6167656e745f68656c7065725f7468726561645f6964 > 00:00:48 Sending packet: $qSymbol::6764625f6167656e745f68656c7065725f7468726561645f6964#4f...Packet received: qSymbol:6764625f6167656e745f636d645f627566 > 00:00:48 Sending packet: $qSymbol::6764625f6167656e745f636d645f627566#5d...Packet received: qSymbol:6e70746c5f76657273696f6e > 00:00:49 Sending packet: $qSymbol::6e70746c5f76657273696f6e#4d...Packet received: qSymbol:6e70746c5f76657273696f6e > 00:00:49 Sending packet: $qSymbol::6e70746c5f76657273696f6e#4d...Packet received: qSymbol:6e70746c5f76657273696f6e > 00:00:49 Sending packet: $qSymbol::6e70746c5f76657273696f6e#4d...Packet received: OK > > Since I have 10 shared libraries in that executable, this costs me about > 1 minute delay, and is completely wasted, because I am not going to use > tracepoints. Most of that querying is actually unnecessary. All the symbols the tracepoints module is looking up are required for libinproctrace.so to be active. So, there's no need to look them all up if any fails to be found, since if any fails, we know we don't have libinproctrace.so loaded yet. In practice, we end up doing one (tracepoint related) query per DSO only. Can you give the patch below a try? We have had this in our tree for months. Hopefuly it'll still apply cleanly. -- Pedro Alves 2011-01-27 Pedro Alves gdb/gdbserver * gdbserver (tracepoint_look_up_symbols): Return upon the first symbol error. Index: gdb/gdbserver/tracepoint.c =================================================================== --- gdb.orig/gdbserver/tracepoint.c 2011-01-26 15:52:39.634522000 -0200 +++ gdb/gdbserver/tracepoint.c 2011-01-26 16:14:59.554522000 -0200 @@ -320,13 +320,11 @@ void tracepoint_look_up_symbols (void) { - int all_ok; int i; if (all_tracepoint_symbols_looked_up) return; - all_ok = 1; for (i = 0; i < sizeof (symbol_list) / sizeof (symbol_list[0]); i++) { CORE_ADDR *addrp = @@ -336,11 +334,11 @@ { if (debug_threads) fprintf (stderr, "symbol `%s' not found\n", symbol_list[i].name); - all_ok = 0; + return; } } - all_tracepoint_symbols_looked_up = all_ok; + all_tracepoint_symbols_looked_up = 1; } #endif