From patchwork Tue Oct 22 10:56:02 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Alex_Benn=C3=A9e?= X-Patchwork-Id: 13845525 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 95988D1CDDC for ; Tue, 22 Oct 2024 10:57:12 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1t3CZH-0001sb-P6; Tue, 22 Oct 2024 06:56:52 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1t3CYw-0001mJ-QL for qemu-devel@nongnu.org; Tue, 22 Oct 2024 06:56:30 -0400 Received: from mail-ed1-x532.google.com ([2a00:1450:4864:20::532]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1t3CYt-00022y-Lm for qemu-devel@nongnu.org; Tue, 22 Oct 2024 06:56:30 -0400 Received: by mail-ed1-x532.google.com with SMTP id 4fb4d7f45d1cf-5c941623a5aso10852690a12.0 for ; Tue, 22 Oct 2024 03:56:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1729594586; x=1730199386; darn=nongnu.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=CnSO5MY5LW+ONfwtsvf8QoavFQHBZ1D8g95DfEWZbMI=; b=krAPCbK6vVfqJ+3Gw5QmJdK5a3cuR7ymepFMHdmSvDd87gWOG11GGntTF0LdknzLKa sJnDV/7xiwJq794JCHFE9xLNeXCetelYhyC92rfmI4MpZ/bbLhx9tmITFxI4sj4ELCxQ QvDajzUwZUsTR/vKHukSyyRz17v2j+igPzjf5b+dnZZiHC4oq7NT4fVSPX9A9B8TODzZ 4OGbBzQqRLPFjQ2jLvrukIEaaZ2qQxJdSj06xGSC/EvWkYOi1lqzfbjnofC1mD8zKrp+ eVH3sDcdDHvXZrBSu1hBqVAdrUjv0o6nZ3XP457CzK9EwzjVZ5b1RzAMRiR0CBzMHYQW In+w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1729594586; x=1730199386; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=CnSO5MY5LW+ONfwtsvf8QoavFQHBZ1D8g95DfEWZbMI=; b=T8OvHCpmPQOnhnOaWiVu3IthQHfykI/9CnLawlLrZthRM2AM2TIO7rwZWtByjRz7Xu 7xI3Hdb/vM2KaXvx1FioXNhyNOYcIPMoA8YthWXcLIGqgHre2dZ6IC7lW9HvW4mMSemU paFFU+YNBAIzDGpTkHc+MTlOhv7cNHG8NOMsVYJPe9KmEN3t0kqBwdQwWyvD5vJIKUn6 kGkGY7rLe9aj52NDK2Ri1Xtau/8LAuEZEjUfhNF3cRsV4CC88OGwcqoanmv1/D7YOqQX vagqB1nCvQaHsyNjHtz/SSLOwEtbKkwfAB0lgppicF0zaJDrUhtWYGy5loCCIQzNbho5 ducA== X-Gm-Message-State: AOJu0YzjugMZ1/36gwso922yw93J88lvbPvaJ2bvnofjqtrzpIwdx87r +xxnUtNPhEQWeeJ4yjcs+orY8R/AvhrvvtWBlS1syP3wsfRZnAYzR0VqKWkI6Oo= X-Google-Smtp-Source: AGHT+IE/K5pr2g0U8BMqLhyIWw7NwWY4cgjvbPeZV6ZYZQj/JnrnlV+snPJRyVIL9w1vqQwf5cuM+A== X-Received: by 2002:a17:907:944e:b0:a9a:3f9c:f89d with SMTP id a640c23a62f3a-a9aaa5ee850mr282522466b.34.1729594586066; Tue, 22 Oct 2024 03:56:26 -0700 (PDT) Received: from draig.lan ([85.9.250.243]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-a9a91559c06sm324381166b.138.2024.10.22.03.56.17 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 22 Oct 2024 03:56:19 -0700 (PDT) Received: from draig.lan (localhost [IPv6:::1]) by draig.lan (Postfix) with ESMTP id 5CB715F9D0; Tue, 22 Oct 2024 11:56:15 +0100 (BST) From: =?utf-8?q?Alex_Benn=C3=A9e?= To: qemu-devel@nongnu.org Cc: Beraldo Leal , Laurent Vivier , Wainer dos Santos Moschetta , Mahmoud Mandour , Jiaxun Yang , =?utf-8?q?Alex_Benn=C3=A9e?= , Yanan Wang , Thomas Huth , John Snow , =?utf-8?q?Marc-Andr=C3=A9_Lureau?= , qemu-arm@nongnu.org, =?utf-8?q?Daniel_P=2E_Berrang=C3=A9?= , Eduardo Habkost , devel@lists.libvirt.org, Cleber Rosa , kvm@vger.kernel.org, =?utf-8?q?Philippe_Mat?= =?utf-8?q?hieu-Daud=C3=A9?= , Alexandre Iooss , Peter Maydell , Richard Henderson , Riku Voipio , Zhao Liu , Marcelo Tosatti , "Edgar E. Iglesias" , Marcel Apfelbaum , Pierrick Bouvier , Paolo Bonzini Subject: [PATCH v2 08/20] accel/tcg: add tracepoints for cpu_loop_exit_atomic Date: Tue, 22 Oct 2024 11:56:02 +0100 Message-Id: <20241022105614.839199-9-alex.bennee@linaro.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20241022105614.839199-1-alex.bennee@linaro.org> References: <20241022105614.839199-1-alex.bennee@linaro.org> MIME-Version: 1.0 Received-SPF: pass client-ip=2a00:1450:4864:20::532; envelope-from=alex.bennee@linaro.org; helo=mail-ed1-x532.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org We try to avoid using cpu_loop_exit_atomic as it brings in an all-core sync point. However on some cpu/kernel/benchmark combinations it is starting to show up in the performance profile. To make it easier to see whats going on add tracepoints for the slow path so we can see what is triggering the wait. It seems for a modern CPU it can be quite a bit, for example: ./qemu-system-aarch64 \ -machine type=virt,virtualization=on,pflash0=rom,pflash1=efivars,gic-version=max \ -smp 4 \ -accel tcg \ -device virtio-net-pci,netdev=unet \ -device virtio-scsi-pci \ -device scsi-hd,drive=hd \ -netdev user,id=unet,hostfwd=tcp::2222-:22 \ -blockdev driver=raw,node-name=hd,file.driver=host_device,file.filename=/dev/zen-ssd2/trixie-arm64,discard=unmap \ -serial mon:stdio \ -blockdev node-name=rom,driver=file,filename=(pwd)/pc-bios/edk2-aarch64-code.fd,read-only=true \ -blockdev node-name=efivars,driver=file,filename=$HOME/images/qemu-arm64-efivars \ -m 8192 \ -object memory-backend-memfd,id=mem,size=8G,share=on \ -kernel /home/alex/lsrc/linux.git/builds/arm64/arch/arm64/boot/Image -append "root=/dev/sda2 console=ttyAMA0 systemd.unit=benchmark-stress-ng.service" \ -display none -d trace:load_atom\*_fallback,trace:store_atom\*_fallback With: -cpu neoverse-v1,pauth-impdef=on => 2203343 With: -cpu cortex-a76 => 0 Signed-off-by: Alex Bennée Reviewed-by: Richard Henderson Reviewed-by: Pierrick Bouvier --- v2 - 0x prefixes for ra as per checkpatch --- accel/tcg/user-exec.c | 2 +- accel/tcg/ldst_atomicity.c.inc | 9 +++++++++ accel/tcg/trace-events | 12 ++++++++++++ 3 files changed, 22 insertions(+), 1 deletion(-) diff --git a/accel/tcg/user-exec.c b/accel/tcg/user-exec.c index 51b2c16dbe..aa8af52cc3 100644 --- a/accel/tcg/user-exec.c +++ b/accel/tcg/user-exec.c @@ -29,7 +29,7 @@ #include "exec/page-protection.h" #include "exec/helper-proto.h" #include "qemu/atomic128.h" -#include "trace/trace-root.h" +#include "trace.h" #include "tcg/tcg-ldst.h" #include "internal-common.h" #include "internal-target.h" diff --git a/accel/tcg/ldst_atomicity.c.inc b/accel/tcg/ldst_atomicity.c.inc index 134da3c1da..c735add261 100644 --- a/accel/tcg/ldst_atomicity.c.inc +++ b/accel/tcg/ldst_atomicity.c.inc @@ -168,6 +168,7 @@ static uint64_t load_atomic8_or_exit(CPUState *cpu, uintptr_t ra, void *pv) #endif /* Ultimate fallback: re-execute in serial context. */ + trace_load_atom8_or_exit_fallback(ra); cpu_loop_exit_atomic(cpu, ra); } @@ -212,6 +213,7 @@ static Int128 load_atomic16_or_exit(CPUState *cpu, uintptr_t ra, void *pv) } /* Ultimate fallback: re-execute in serial context. */ + trace_load_atom16_or_exit_fallback(ra); cpu_loop_exit_atomic(cpu, ra); } @@ -519,6 +521,7 @@ static uint64_t load_atom_8(CPUState *cpu, uintptr_t ra, if (HAVE_al8) { return load_atom_extract_al8x2(pv); } + trace_load_atom8_fallback(memop, ra); cpu_loop_exit_atomic(cpu, ra); default: g_assert_not_reached(); @@ -563,6 +566,7 @@ static Int128 load_atom_16(CPUState *cpu, uintptr_t ra, break; case MO_64: if (!HAVE_al8) { + trace_load_atom16_fallback(memop, ra); cpu_loop_exit_atomic(cpu, ra); } a = load_atomic8(pv); @@ -570,6 +574,7 @@ static Int128 load_atom_16(CPUState *cpu, uintptr_t ra, break; case -MO_64: if (!HAVE_al8) { + trace_load_atom16_fallback(memop, ra); cpu_loop_exit_atomic(cpu, ra); } a = load_atom_extract_al8x2(pv); @@ -897,6 +902,7 @@ static void store_atom_2(CPUState *cpu, uintptr_t ra, g_assert_not_reached(); } + trace_store_atom2_fallback(memop, ra); cpu_loop_exit_atomic(cpu, ra); } @@ -961,6 +967,7 @@ static void store_atom_4(CPUState *cpu, uintptr_t ra, return; } } + trace_store_atom4_fallback(memop, ra); cpu_loop_exit_atomic(cpu, ra); default: g_assert_not_reached(); @@ -1029,6 +1036,7 @@ static void store_atom_8(CPUState *cpu, uintptr_t ra, default: g_assert_not_reached(); } + trace_store_atom8_fallback(memop, ra); cpu_loop_exit_atomic(cpu, ra); } @@ -1107,5 +1115,6 @@ static void store_atom_16(CPUState *cpu, uintptr_t ra, default: g_assert_not_reached(); } + trace_store_atom16_fallback(memop, ra); cpu_loop_exit_atomic(cpu, ra); } diff --git a/accel/tcg/trace-events b/accel/tcg/trace-events index 4e9b450520..14f638810c 100644 --- a/accel/tcg/trace-events +++ b/accel/tcg/trace-events @@ -12,3 +12,15 @@ memory_notdirty_set_dirty(uint64_t vaddr) "0x%" PRIx64 # translate-all.c translate_block(void *tb, uintptr_t pc, const void *tb_code) "tb:%p, pc:0x%"PRIxPTR", tb_code:%p" + +# ldst_atomicity +load_atom2_fallback(uint32_t memop, uintptr_t ra) "mop:0x%"PRIx32", ra:0x%"PRIxPTR"" +load_atom4_fallback(uint32_t memop, uintptr_t ra) "mop:0x%"PRIx32", ra:0x%"PRIxPTR"" +load_atom8_or_exit_fallback(uintptr_t ra) "ra:0x%"PRIxPTR"" +load_atom8_fallback(uint32_t memop, uintptr_t ra) "mop:0x%"PRIx32", ra:0x%"PRIxPTR"" +load_atom16_fallback(uint32_t memop, uintptr_t ra) "mop:0x%"PRIx32", ra:0x%"PRIxPTR"" +load_atom16_or_exit_fallback(uintptr_t ra) "ra:0x%"PRIxPTR"" +store_atom2_fallback(uint32_t memop, uintptr_t ra) "mop:0x%"PRIx32", ra:0x%"PRIxPTR"" +store_atom4_fallback(uint32_t memop, uintptr_t ra) "mop:0x%"PRIx32", ra:0x%"PRIxPTR"" +store_atom8_fallback(uint32_t memop, uintptr_t ra) "mop:0x%"PRIx32", ra:0x%"PRIxPTR"" +store_atom16_fallback(uint32_t memop, uintptr_t ra) "mop:0x%"PRIx32", ra:0x%"PRIxPTR""