From patchwork Wed Jan 31 14:18:44 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Marco Elver X-Patchwork-Id: 768690 Received: from mail-ed1-f74.google.com (mail-ed1-f74.google.com [209.85.208.74]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9BC9C69D00 for ; Wed, 31 Jan 2024 14:19:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.208.74 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706710759; cv=none; b=X0cUhrlOzggk1NR2gL2ZVIG/AdIxWlhk9SZlqn6FGXYdmqjX84u1pER1qNnE6R+nFOXqFTPpyYSxJgOZBcwWixJQQVlvhDJMECVm8BQ2Pdm3F2ZepXXhDKNp07E7wIJA2AccKy27W40mQuLC/+PIutB/IYmqAizLHjqORkx7ZkU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706710759; c=relaxed/simple; bh=YvsXE9OR+IUltygOycGvea6KYYgI+LiZAiXelBwbSdw=; h=Date:Mime-Version:Message-ID:Subject:From:To:Cc:Content-Type; b=AhT5xLsrEw+yQce4MfmTPmK2mmFAosCnplBd+4A51wdBfzjJsm3xI7LtKq6fZYO4MQ9DB2BKYg2LjvQ5OSMS18d6zv4CHYBsE50guq+NSKo2dKrX58iZFuKeAIGX1fY+3iCWaG9gFnVNOJi0UQsHyzHUbRbwN2lDKK2Ri4JsMGo= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--elver.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=a5mJQCFU; arc=none smtp.client-ip=209.85.208.74 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--elver.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="a5mJQCFU" Received: by mail-ed1-f74.google.com with SMTP id 4fb4d7f45d1cf-55f12bced3bso1818682a12.0 for ; Wed, 31 Jan 2024 06:19:15 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1706710754; x=1707315554; darn=vger.kernel.org; h=content-transfer-encoding:cc:to:from:subject:message-id :mime-version:date:from:to:cc:subject:date:message-id:reply-to; bh=IaMeGJ0rWB78uo9A8Je3r+q2sT9bnmMm16vK1tzleA8=; b=a5mJQCFUZ+lU3jx08r2hDwm5++dAbuUrLC2LtD1xYZJXj3lrT1/L+L27zWBxdw2RCX Bwtr95WvVu0zIeK5K4iABYM2SxXmmGx9y6LYZOKKTBu5bIsmkp/J+j7o9FRM3dc8tpir MKd2t1OuABcbcxFrXbk0YCdNcXqaly0Zsa9cc075rL9sFn2AMvU5qAewT+d4+sKKpy6Y F2RO9dK2Ctp0VOpEhksqHSUE14AF6Y+snbrdNRsJN47l8Cqs4rOF9reQ8a3LD6pW2RT8 6RysvzfjIoT3+82XV3yQgamNqak1DdDdswuR8f58/2EomOp96uB1V4Rywq3J7v5m8sI6 SmmA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1706710754; x=1707315554; h=content-transfer-encoding:cc:to:from:subject:message-id :mime-version:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=IaMeGJ0rWB78uo9A8Je3r+q2sT9bnmMm16vK1tzleA8=; b=iGpzpeWrFXp7+7bAMCr7ulzmdd1gmuktKbm5CqDl0JKR7fe8JBkI/dodQRR9ithvjy fH7et+ngw7LhK/04kevhPX0k/o994IHHGUoGmC9b1HxV8pHs3nKk/q4UmL/K4inDQFx7 TE4QCRnJh65t9YP0OTsC7w9nVneKQlw7Rgqkz1XJ0ozwsi5DOnH98sii0gs4XHK8QdVR v403AdZcIBOjwSIM289QxVvaBqPM1mkyJWzqBI8WBltGLyDTlyrWgwwLdvZS1BOyuhQz /VjdkxB0RqlRH8f6Z//umeQsR3ggsAu/i8iSXntuupZh1HXmmW/YV4w7Nrva7iarA6FS WXhw== X-Gm-Message-State: AOJu0YwSffpEL7apXkoLBzwDTNRDXEGMXuRIErhJebQQpYyFu3fzzJ0k smWE8FVQ+90ueugCB7Zkp1AVualcdfZlgOj45H2xp1BVvWn2W745O0b72NkZxwqe4or4lE0UBA= = X-Google-Smtp-Source: AGHT+IH1fksSvzeQMmagfUyODYTJ4E+QON8T+tLm4xKVfBz5TBUVM3L+OZBAqEMtOoqN7+rXMWq6gbQOIA== X-Received: from elver.muc.corp.google.com ([2a00:79e0:9c:201:5727:e5f5:9cb8:3c6e]) (user=elver job=sendgmr) by 2002:a05:6402:b87:b0:55e:f9f8:9025 with SMTP id cf7-20020a0564020b8700b0055ef9f89025mr3587edb.3.1706710753556; Wed, 31 Jan 2024 06:19:13 -0800 (PST) Date: Wed, 31 Jan 2024 15:18:44 +0100 Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 X-Mailer: git-send-email 2.43.0.429.g432eaa2c6b-goog Message-ID: <20240131141858.1149719-1-elver@google.com> Subject: [PATCH] bpf: Separate bpf_local_storage_lookup() fast and slow paths From: Marco Elver To: elver@google.com Cc: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , Stanislav Fomichev , Hao Luo , Jiri Olsa , Mykola Lysenko , Shuah Khan , bpf@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org To allow the compiler to inline the bpf_local_storage_lookup() fast- path, factor it out by making bpf_local_storage_lookup() a static inline function and move the slow-path to bpf_local_storage_lookup_slowpath(). Base on results from './benchs/run_bench_local_storage.sh' this produces improvements in throughput and latency in the majority of cases: | Hashmap Control | =============== | num keys: 10 | hashmap (control) sequential get: | | | hits throughput: 13.895 ± 0.024 M ops/s | 14.022 ± 0.095 M ops/s (+0.9%) | hits latency: 71.968 ns/op | 71.318 ns/op (-0.9%) | important_hits throughput: 13.895 ± 0.024 M ops/s | 14.022 ± 0.095 M ops/s (+0.9%) | | num keys: 1000 | hashmap (control) sequential get: | | | hits throughput: 11.793 ± 0.018 M ops/s | 11.645 ± 0.370 M ops/s (-1.3%) | hits latency: 84.794 ns/op | 85.874 ns/op (+1.3%) | important_hits throughput: 11.793 ± 0.018 M ops/s | 11.645 ± 0.370 M ops/s (-1.3%) | | num keys: 10000 | hashmap (control) sequential get: | | | hits throughput: 7.113 ± 0.012 M ops/s | 7.037 ± 0.051 M ops/s (-1.1%) | hits latency: 140.581 ns/op | 142.113 ns/op (+1.1%) | important_hits throughput: 7.113 ± 0.012 M ops/s | 7.037 ± 0.051 M ops/s (-1.1%) | | num keys: 100000 | hashmap (control) sequential get: | | | hits throughput: 4.793 ± 0.034 M ops/s | 4.990 ± 0.025 M ops/s (+4.1%) | hits latency: 208.623 ns/op | 200.401 ns/op (-3.9%) | important_hits throughput: 4.793 ± 0.034 M ops/s | 4.990 ± 0.025 M ops/s (+4.1%) | | num keys: 4194304 | hashmap (control) sequential get: | | | hits throughput: 2.088 ± 0.008 M ops/s | 2.962 ± 0.004 M ops/s (+41.9%) | hits latency: 478.851 ns/op | 337.648 ns/op (-29.5%) | important_hits throughput: 2.088 ± 0.008 M ops/s | 2.962 ± 0.004 M ops/s (+41.9%) | | Local Storage | ============= | num_maps: 1 | local_storage cache sequential get: | | | hits throughput: 32.598 ± 0.008 M ops/s | 38.480 ± 0.054 M ops/s (+18.0%) | hits latency: 30.676 ns/op | 25.988 ns/op (-15.3%) | important_hits throughput: 32.598 ± 0.008 M ops/s | 38.480 ± 0.054 M ops/s (+18.0%) | local_storage cache interleaved get: | | | hits throughput: 36.963 ± 0.045 M ops/s | 43.847 ± 0.037 M ops/s (+18.6%) | hits latency: 27.054 ns/op | 22.807 ns/op (-15.7%) | important_hits throughput: 36.963 ± 0.045 M ops/s | 43.847 ± 0.037 M ops/s (+18.6%) | | num_maps: 10 | local_storage cache sequential get: | | | hits throughput: 32.078 ± 0.004 M ops/s | 37.813 ± 0.020 M ops/s (+17.9%) | hits latency: 31.174 ns/op | 26.446 ns/op (-15.2%) | important_hits throughput: 3.208 ± 0.000 M ops/s | 3.781 ± 0.002 M ops/s (+17.9%) | local_storage cache interleaved get: | | | hits throughput: 34.564 ± 0.011 M ops/s | 40.082 ± 0.037 M ops/s (+16.0%) | hits latency: 28.932 ns/op | 24.949 ns/op (-13.8%) | important_hits throughput: 12.344 ± 0.004 M ops/s | 14.315 ± 0.013 M ops/s (+16.0%) | | num_maps: 16 | local_storage cache sequential get: | | | hits throughput: 32.493 ± 0.023 M ops/s | 38.147 ± 0.029 M ops/s (+17.4%) | hits latency: 30.776 ns/op | 26.215 ns/op (-14.8%) | important_hits throughput: 2.031 ± 0.001 M ops/s | 2.384 ± 0.002 M ops/s (+17.4%) | local_storage cache interleaved get: | | | hits throughput: 34.380 ± 0.521 M ops/s | 41.605 ± 0.095 M ops/s (+21.0%) | hits latency: 29.087 ns/op | 24.035 ns/op (-17.4%) | important_hits throughput: 10.939 ± 0.166 M ops/s | 13.238 ± 0.030 M ops/s (+21.0%) | | num_maps: 17 | local_storage cache sequential get: | | | hits throughput: 28.748 ± 0.028 M ops/s | 32.248 ± 0.080 M ops/s (+12.2%) | hits latency: 34.785 ns/op | 31.009 ns/op (-10.9%) | important_hits throughput: 1.693 ± 0.002 M ops/s | 1.899 ± 0.005 M ops/s (+12.2%) | local_storage cache interleaved get: | | | hits throughput: 31.313 ± 0.030 M ops/s | 35.911 ± 0.020 M ops/s (+14.7%) | hits latency: 31.936 ns/op | 27.847 ns/op (-12.8%) | important_hits throughput: 9.533 ± 0.009 M ops/s | 10.933 ± 0.006 M ops/s (+14.7%) | | num_maps: 24 | local_storage cache sequential get: | | | hits throughput: 18.475 ± 0.027 M ops/s | 19.000 ± 0.006 M ops/s (+2.8%) | hits latency: 54.127 ns/op | 52.632 ns/op (-2.8%) | important_hits throughput: 0.770 ± 0.001 M ops/s | 0.792 ± 0.000 M ops/s (+2.9%) | local_storage cache interleaved get: | | | hits throughput: 21.361 ± 0.028 M ops/s | 22.388 ± 0.099 M ops/s (+4.8%) | hits latency: 46.814 ns/op | 44.667 ns/op (-4.6%) | important_hits throughput: 6.009 ± 0.008 M ops/s | 6.298 ± 0.028 M ops/s (+4.8%) | | num_maps: 32 | local_storage cache sequential get: | | | hits throughput: 14.220 ± 0.006 M ops/s | 14.168 ± 0.020 M ops/s (-0.4%) | hits latency: 70.323 ns/op | 70.580 ns/op (+0.4%) | important_hits throughput: 0.445 ± 0.000 M ops/s | 0.443 ± 0.001 M ops/s (-0.4%) | local_storage cache interleaved get: | | | hits throughput: 17.250 ± 0.011 M ops/s | 16.650 ± 0.021 M ops/s (-3.5%) | hits latency: 57.971 ns/op | 60.061 ns/op (+3.6%) | important_hits throughput: 4.815 ± 0.003 M ops/s | 4.647 ± 0.006 M ops/s (-3.5%) | | num_maps: 100 | local_storage cache sequential get: | | | hits throughput: 5.212 ± 0.012 M ops/s | 5.878 ± 0.004 M ops/s (+12.8%) | hits latency: 191.877 ns/op | 170.116 ns/op (-11.3%) | important_hits throughput: 0.052 ± 0.000 M ops/s | 0.059 ± 0.000 M ops/s (+13.5%) | local_storage cache interleaved get: | | | hits throughput: 6.521 ± 0.053 M ops/s | 7.086 ± 0.010 M ops/s (+8.7%) | hits latency: 153.343 ns/op | 141.116 ns/op (-8.0%) | important_hits throughput: 1.703 ± 0.014 M ops/s | 1.851 ± 0.003 M ops/s (+8.7%) | | num_maps: 1000 | local_storage cache sequential get: | | | hits throughput: 0.357 ± 0.005 M ops/s | 0.325 ± 0.005 M ops/s (-9.0%) | hits latency: 2803.738 ns/op | 3076.923 ns/op (+9.7%) | important_hits throughput: 0.000 ± 0.000 M ops/s | 0.000 ± 0.000 M ops/s | local_storage cache interleaved get: | | | hits throughput: 0.434 ± 0.007 M ops/s | 0.447 ± 0.007 M ops/s (+3.0%) | hits latency: 2306.539 ns/op | 2237.687 ns/op (-3.0%) | important_hits throughput: 0.109 ± 0.002 M ops/s | 0.112 ± 0.002 M ops/s (+2.8%) Signed-off-by: Marco Elver --- include/linux/bpf_local_storage.h | 17 ++++++++++++++++- kernel/bpf/bpf_local_storage.c | 14 ++++---------- .../selftests/bpf/progs/cgrp_ls_recursion.c | 2 +- .../selftests/bpf/progs/task_ls_recursion.c | 2 +- 4 files changed, 22 insertions(+), 13 deletions(-) diff --git a/include/linux/bpf_local_storage.h b/include/linux/bpf_local_storage.h index 173ec7f43ed1..c8cecf7fff87 100644 --- a/include/linux/bpf_local_storage.h +++ b/include/linux/bpf_local_storage.h @@ -130,9 +130,24 @@ bpf_local_storage_map_alloc(union bpf_attr *attr, bool bpf_ma); struct bpf_local_storage_data * +bpf_local_storage_lookup_slowpath(struct bpf_local_storage *local_storage, + struct bpf_local_storage_map *smap, + bool cacheit_lockit); +static inline struct bpf_local_storage_data * bpf_local_storage_lookup(struct bpf_local_storage *local_storage, struct bpf_local_storage_map *smap, - bool cacheit_lockit); + bool cacheit_lockit) +{ + struct bpf_local_storage_data *sdata; + + /* Fast path (cache hit) */ + sdata = rcu_dereference_check(local_storage->cache[smap->cache_idx], + bpf_rcu_lock_held()); + if (likely(sdata && rcu_access_pointer(sdata->smap) == smap)) + return sdata; + + return bpf_local_storage_lookup_slowpath(local_storage, smap, cacheit_lockit); +} void bpf_local_storage_destroy(struct bpf_local_storage *local_storage); diff --git a/kernel/bpf/bpf_local_storage.c b/kernel/bpf/bpf_local_storage.c index 146824cc9689..2ef782a1bd6f 100644 --- a/kernel/bpf/bpf_local_storage.c +++ b/kernel/bpf/bpf_local_storage.c @@ -415,20 +415,14 @@ void bpf_selem_unlink(struct bpf_local_storage_elem *selem, bool reuse_now) } /* If cacheit_lockit is false, this lookup function is lockless */ -struct bpf_local_storage_data * -bpf_local_storage_lookup(struct bpf_local_storage *local_storage, - struct bpf_local_storage_map *smap, - bool cacheit_lockit) +noinline struct bpf_local_storage_data * +bpf_local_storage_lookup_slowpath(struct bpf_local_storage *local_storage, + struct bpf_local_storage_map *smap, + bool cacheit_lockit) { struct bpf_local_storage_data *sdata; struct bpf_local_storage_elem *selem; - /* Fast path (cache hit) */ - sdata = rcu_dereference_check(local_storage->cache[smap->cache_idx], - bpf_rcu_lock_held()); - if (sdata && rcu_access_pointer(sdata->smap) == smap) - return sdata; - /* Slow path (cache miss) */ hlist_for_each_entry_rcu(selem, &local_storage->list, snode, rcu_read_lock_trace_held()) diff --git a/tools/testing/selftests/bpf/progs/cgrp_ls_recursion.c b/tools/testing/selftests/bpf/progs/cgrp_ls_recursion.c index a043d8fefdac..9895087a9235 100644 --- a/tools/testing/selftests/bpf/progs/cgrp_ls_recursion.c +++ b/tools/testing/selftests/bpf/progs/cgrp_ls_recursion.c @@ -21,7 +21,7 @@ struct { __type(value, long); } map_b SEC(".maps"); -SEC("fentry/bpf_local_storage_lookup") +SEC("fentry/bpf_local_storage_lookup_slowpath") int BPF_PROG(on_lookup) { struct task_struct *task = bpf_get_current_task_btf(); diff --git a/tools/testing/selftests/bpf/progs/task_ls_recursion.c b/tools/testing/selftests/bpf/progs/task_ls_recursion.c index 4542dc683b44..d73b33a4c153 100644 --- a/tools/testing/selftests/bpf/progs/task_ls_recursion.c +++ b/tools/testing/selftests/bpf/progs/task_ls_recursion.c @@ -27,7 +27,7 @@ struct { __type(value, long); } map_b SEC(".maps"); -SEC("fentry/bpf_local_storage_lookup") +SEC("fentry/bpf_local_storage_lookup_slowpath") int BPF_PROG(on_lookup) { struct task_struct *task = bpf_get_current_task_btf();