[{"id":1768069,"web_url":"http://patchwork.ozlabs.org/comment/1768069/","msgid":"<418914ee-c8bf-2576-3cea-4a3eb2a9d4f7@linaro.org>","list_archive_url":null,"date":"2017-09-13T18:01:39","subject":"Re: [Qemu-devel] [PATCH 6/7] trace: Add event \"guest_inst_after\"","submitter":{"id":72104,"url":"http://patchwork.ozlabs.org/api/people/72104/","name":"Richard Henderson","email":"richard.henderson@linaro.org"},"content":"On 09/10/2017 09:35 AM, Lluís Vilanova wrote:\n> Signed-off-by: Lluís Vilanova \n> ---\n> accel/tcg/translator.c | 23 ++++++++++++++++++-----\n> trace-events | 8 ++++++++\n> 2 files changed, 26 insertions(+), 5 deletions(-)\n> \n> diff --git a/accel/tcg/translator.c b/accel/tcg/translator.c\n> index d66d601c89..c010aeee45 100644\n> --- a/accel/tcg/translator.c\n> +++ b/accel/tcg/translator.c\n> @@ -35,7 +35,8 @@ void translator_loop_temp_check(DisasContextBase *db)\n> void translator_loop(const TranslatorOps *ops, DisasContextBase *db,\n> CPUState *cpu, TranslationBlock *tb)\n> {\n> - target_ulong pc_bbl;\n> + target_ulong pc_bbl, pc_insn = 0;\n> + bool translated_insn = false;\n> int max_insns;\n> \n> /* Initialize DisasContext */\n> @@ -75,10 +76,15 @@ void translator_loop(const TranslatorOps *ops, DisasContextBase *db,\n> tcg_debug_assert(db->is_jmp == DISAS_NEXT); /* no early exit */\n> \n> while (true) {\n> - target_ulong pc_insn = db->pc_next;\n> TCGv_i32 insn_size_tcg = 0;\n> int insn_size_opcode_idx;\n> \n> + /* Tracing after (previous instruction) */\n> + if (db->num_insns > 0) {\n> + trace_guest_inst_after_tcg(cpu, tcg_ctx.tcg_env, pc_insn);\n> + }\n\nHow does this differ from \"guest_inst\"? Why would you need two trace points?\n\nWhy are you placing this at the beginning of the while loop rather than the end?\n\n> @@ -164,6 +172,9 @@ void translator_loop(const TranslatorOps *ops, DisasContextBase *db,\n> \n> gen_set_inline_region_begin(tcg_ctx.disas.inline_label);\n> \n> + if (TRACE_GUEST_INST_AFTER_ENABLED && translated_insn) {\n> + trace_guest_inst_after_tcg(cpu, tcg_ctx.tcg_env, pc_insn);\n> + }\n> if (TRACE_GUEST_BBL_AFTER_ENABLED) {\n> trace_guest_bbl_after_tcg(cpu, tcg_ctx.tcg_env, pc_bbl);\n> }\n\nI think I'm finally beginning to understand what you're after with your\ninlining. But I still think this should be doable in the appropriate opcode\ngenerating functions.\n\n\nr~","headers":{"Return-Path":"","X-Original-To":"incoming@patchwork.ozlabs.org","Delivered-To":"patchwork-incoming@bilbo.ozlabs.org","Authentication-Results":["ozlabs.org;\n\tspf=pass (mailfrom) smtp.mailfrom=nongnu.org\n\t(client-ip=2001:4830:134:3::11; helo=lists.gnu.org;\n\tenvelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org;\n\treceiver=)","ozlabs.org;\n\tdkim=fail reason=\"signature verification failed\" (1024-bit key;\n\tunprotected) header.d=linaro.org header.i=@linaro.org\n\theader.b=\"JqXWQWHD\"; dkim-atps=neutral"],"Received":["from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11])\n\t(using TLSv1 with cipher AES256-SHA (256/256 bits))\n\t(No client certificate requested)\n\tby ozlabs.org (Postfix) with ESMTPS id 3xsqKB4Tw2z9s7v\n\tfor ;\n\tThu, 14 Sep 2017 04:03:26 +1000 (AEST)","from localhost ([::1]:43930 helo=lists.gnu.org)\n\tby lists.gnu.org with esmtp (Exim 4.71) (envelope-from\n\t)\n\tid 1dsC0S-0006F7-Pc\n\tfor incoming@patchwork.ozlabs.org; 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Linux x86_64; rv:52.0) Gecko/20100101\n\tThunderbird/52.3.0","MIME-Version":"1.0","In-Reply-To":"<150506131942.19604.1306593039321280342.stgit@frigg.lan>","Content-Type":"text/plain; charset=utf-8","Content-Language":"en-US","Content-Transfer-Encoding":"8bit","X-detected-operating-system":"by eggs.gnu.org: Genre and OS details not\n\trecognized.","X-Received-From":"2607:f8b0:400d:c0d::22f","Subject":"Re: [Qemu-devel] [PATCH 6/7] trace: Add event \"guest_inst_after\"","X-BeenThere":"qemu-devel@nongnu.org","X-Mailman-Version":"2.1.21","Precedence":"list","List-Id":"","List-Unsubscribe":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","Cc":"Paolo Bonzini ,\n\tPeter Crosthwaite ,\n\tStefan Hajnoczi ,\n\tRichard Henderson ","Errors-To":"qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org","Sender":"\"Qemu-devel\"\n\t"}},{"id":1768718,"web_url":"http://patchwork.ozlabs.org/comment/1768718/","msgid":"<877ex1nta1.fsf@frigg.lan>","list_archive_url":null,"date":"2017-09-14T16:23:34","subject":"Re: [Qemu-devel] [PATCH 6/7] trace: Add event \"guest_inst_after\"","submitter":{"id":9099,"url":"http://patchwork.ozlabs.org/api/people/9099/","name":"Lluís Vilanova","email":"vilanova@ac.upc.edu"},"content":"Richard Henderson writes:\n\n> On 09/10/2017 09:35 AM, Lluís Vilanova wrote:\n>> Signed-off-by: Lluís Vilanova \n>> ---\n>> accel/tcg/translator.c | 23 ++++++++++++++++++-----\n>> trace-events | 8 ++++++++\n>> 2 files changed, 26 insertions(+), 5 deletions(-)\n>> \n>> diff --git a/accel/tcg/translator.c b/accel/tcg/translator.c\n>> index d66d601c89..c010aeee45 100644\n>> --- a/accel/tcg/translator.c\n>> +++ b/accel/tcg/translator.c\n>> @@ -35,7 +35,8 @@ void translator_loop_temp_check(DisasContextBase *db)\n>> void translator_loop(const TranslatorOps *ops, DisasContextBase *db,\n>> CPUState *cpu, TranslationBlock *tb)\n>> {\n>> - target_ulong pc_bbl;\n>> + target_ulong pc_bbl, pc_insn = 0;\n>> + bool translated_insn = false;\n>> int max_insns;\n>> \n>> /* Initialize DisasContext */\n>> @@ -75,10 +76,15 @@ void translator_loop(const TranslatorOps *ops, DisasContextBase *db,\n>> tcg_debug_assert(db->is_jmp == DISAS_NEXT); /* no early exit */\n>> \n>> while (true) {\n>> - target_ulong pc_insn = db->pc_next;\n>> TCGv_i32 insn_size_tcg = 0;\n>> int insn_size_opcode_idx;\n>> \n>> + /* Tracing after (previous instruction) */\n>> + if (db->num_insns > 0) {\n>> + trace_guest_inst_after_tcg(cpu, tcg_ctx.tcg_env, pc_insn);\n>> + }\n\n> How does this differ from \"guest_inst\"? Why would you need two trace points?\n\nI assume you mean how it differs from guest_inst_before. The two main ideas are:\n\n* To be able to get a trace an execution-time event only after the instruction\n or TB have finished executing successfully (i.e., there could be an exception).\n* Some values are only known *after* the instruction is translated (like the\n instruction size, or other extra information we might add in the future), so\n an efficient way to collect that is to trace guest_bbl_* and guest_insn_after\n at translation time (to build a TB \"dictionary\" as some call it), and trace\n guest_bbl_before at execution time (and use the detailed info above that you\n got at translation time).\n\n\n> Why are you placing this at the beginning of the while loop rather than the end?\n\nYeah, that'll be much clearer.\n\n\n>> @@ -164,6 +172,9 @@ void translator_loop(const TranslatorOps *ops, DisasContextBase *db,\n>> \n>> gen_set_inline_region_begin(tcg_ctx.disas.inline_label);\n>> \n>> + if (TRACE_GUEST_INST_AFTER_ENABLED && translated_insn) {\n>> + trace_guest_inst_after_tcg(cpu, tcg_ctx.tcg_env, pc_insn);\n>> + }\n>> if (TRACE_GUEST_BBL_AFTER_ENABLED) {\n>> trace_guest_bbl_after_tcg(cpu, tcg_ctx.tcg_env, pc_bbl);\n>> }\n\n> I think I'm finally beginning to understand what you're after with your\n> inlining. But I still think this should be doable in the appropriate opcode\n> generating functions.\n\nI'm not sure we can if we want to avoid having the duplicate translation-time\nevents I said in a previous response (since TB can have two exit points and\nwe're detecting them through goto_tb).\n\n\nThanks,\n Lluis","headers":{"Return-Path":"","X-Original-To":"incoming@patchwork.ozlabs.org","Delivered-To":"patchwork-incoming@bilbo.ozlabs.org","Authentication-Results":"ozlabs.org;\n\tspf=pass (mailfrom) smtp.mailfrom=nongnu.org\n\t(client-ip=2001:4830:134:3::11; helo=lists.gnu.org;\n\tenvelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org;\n\treceiver=)","Received":["from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11])\n\t(using TLSv1 with cipher AES256-SHA (256/256 bits))\n\t(No client certificate requested)\n\tby ozlabs.org (Postfix) with ESMTPS id 3xtP4C5Q1Wz9sPs\n\tfor ;\n\tFri, 15 Sep 2017 02:24:11 +1000 (AEST)","from localhost ([::1]:48832 helo=lists.gnu.org)\n\tby lists.gnu.org with esmtp (Exim 4.71) (envelope-from\n\t)\n\tid 1dsWvx-0002Wh-Sz\n\tfor incoming@patchwork.ozlabs.org; Thu, 14 Sep 2017 12:24:09 -0400","from eggs.gnu.org ([2001:4830:134:3::10]:50317)\n\tby lists.gnu.org with esmtp (Exim 4.71)\n\t(envelope-from ) id 1dsWve-0002Wa-Bj\n\tfor qemu-devel@nongnu.org; Thu, 14 Sep 2017 12:23:51 -0400","from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)\n\t(envelope-from ) id 1dsWvb-0006n9-6K\n\tfor qemu-devel@nongnu.org; Thu, 14 Sep 2017 12:23:50 -0400","from roura.ac.upc.edu ([147.83.33.10]:50510 helo=roura.ac.upc.es)\n\tby eggs.gnu.org with esmtp (Exim 4.71)\n\t(envelope-from ) id 1dsWva-0006mB-QQ\n\tfor qemu-devel@nongnu.org; Thu, 14 Sep 2017 12:23:47 -0400","from correu-2.ac.upc.es (correu-2.ac.upc.es [147.83.30.92])\n\tby roura.ac.upc.es (8.13.8/8.13.8) with ESMTP id v8EGNfDL022091;\n\tThu, 14 Sep 2017 18:23:41 +0200","from localhost (unknown [132.68.50.201])\n\tby correu-2.ac.upc.es (Postfix) with ESMTPSA id 1A20A358;\n\tThu, 14 Sep 2017 18:23:35 +0200 (CEST)"],"From":"=?utf-8?q?Llu=C3=ADs_Vilanova?= ","To":"Richard Henderson ","References":"<150505986682.19604.11937392314067517230.stgit@frigg.lan>\n\t<150506131942.19604.1306593039321280342.stgit@frigg.lan>\n\t<418914ee-c8bf-2576-3cea-4a3eb2a9d4f7@linaro.org>","Mail-Followup-To":"Richard Henderson ,\n\tqemu-devel@nongnu.org, Paolo Bonzini , Richard\n\tHenderson , Stefan Hajnoczi ,\n\tPeter Crosthwaite ","Date":"Thu, 14 Sep 2017 19:23:34 +0300","In-Reply-To":"<418914ee-c8bf-2576-3cea-4a3eb2a9d4f7@linaro.org> (Richard\n\tHenderson's message of \"Wed, 13 Sep 2017 11:01:39 -0700\")","Message-ID":"<877ex1nta1.fsf@frigg.lan>","User-Agent":"Gnus/5.13 (Gnus v5.13) Emacs/25.2 (gnu/linux)","MIME-Version":"1.0","Content-Type":"text/plain; charset=utf-8","Content-Transfer-Encoding":"quoted-printable","X-detected-operating-system":"by eggs.gnu.org: GNU/Linux 2.6.x [fuzzy]","X-Received-From":"147.83.33.10","Subject":"Re: [Qemu-devel] [PATCH 6/7] trace: Add event \"guest_inst_after\"","X-BeenThere":"qemu-devel@nongnu.org","X-Mailman-Version":"2.1.21","Precedence":"list","List-Id":"","List-Unsubscribe":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","Cc":"Paolo Bonzini ,\n\tPeter Crosthwaite ,\n\tqemu-devel@nongnu.org, Stefan Hajnoczi ,\n\tRichard Henderson ","Errors-To":"qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org","Sender":"\"Qemu-devel\"\n\t"}}]