From mboxrd@z Thu Jan 1 00:00:00 1970 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id F3DAFC19F2C for ; Wed, 3 Aug 2022 17:28:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237814AbiHCR2v (ORCPT ); Wed, 3 Aug 2022 13:28:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38318 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234206AbiHCR2v (ORCPT ); Wed, 3 Aug 2022 13:28:51 -0400 Received: from mail-ej1-x629.google.com (mail-ej1-x629.google.com [IPv6:2a00:1450:4864:20::629]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 537B854CBD; Wed, 3 Aug 2022 10:28:49 -0700 (PDT) Received: by mail-ej1-x629.google.com with SMTP id a7so19730826ejp.2; Wed, 03 Aug 2022 10:28:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc; bh=agVoYt1VG5qsMQ9JYe4JEPFq+nuCJIK9+LPfhBj53cg=; b=mcqU+cFDb27B3ksX+sdAGZ9R4qRKk2EcQHiEk0aiCDPJ5Ghvp+1/dJXh+wa0uViODF 3RmjmZ4RhcnMZM3w3Y9R7+Oo7ALZhIeTCUewVnrkxDMJ+w+M4gf+fpU3gaUsS86Ab+8+ KgQrrrYaKGRD6s38WF7btIYxvfGSszab1QFeQx/br5hfhFrh4gxqSpS1wyAlMm8ZeLRe 9inX9f1ePtR60pexvKMBT+g8YaBgCTCIrKxwlZh2ZZJhYWXJ1ggCiJy60Df4BRjYnr9G mJSJPMsthIUioUyWDxAexsEPzcKQeJoyrjdO6M07WRkahcsjg4Cq6ACsEuqj9QOucgD4 IjTg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc; bh=agVoYt1VG5qsMQ9JYe4JEPFq+nuCJIK9+LPfhBj53cg=; b=QPujIHVF7Ub0F4tbHyp9qc5RrcEZYsvhVdPsqHKpqrRcStK7otuo6z0eZ23RLwcAWV SbQ1evl9Q/O+bSg3FlAUKuR+GFccPMFpgJJako2NMGt31fzJB+M91dNveZItGDAhbwWJ w98NFmjohCW9dGc1CHgRuPy+O/rY88cTXHGRsyBsvba2+9XBrKRoc/xuoJEUYSbt9fs1 WabsoM3LYT42539Lr8Y5iL8mJzpw1Wha+O9yXUVkloqoD/jf9TfwsPUgtWkFMUjSPlJ2 Akvf1qUICsrWoyuIgKA+LC2NRssuciZxH0M4yV65FLJShjyfWQmT+k6qrBpUFzJKwxld t3tQ== X-Gm-Message-State: AJIora/p7PHeHnosAk09fChU2JeHbkjDbZlOxl0JN8X6VQUfTex4T+Ld maacD2h8k24JnnXlK36PQa7Y1oaZ5HlbHa0JD5k= X-Google-Smtp-Source: AGRyM1tS8tV2I7KwfPPQYk0TciS595GLvnZoTg76Ou7VlivRU6mTt7rU080/yE1hfXDvUXtzCSgoIYWqBtqbN+sL2P0= X-Received: by 2002:a17:907:6e1d:b0:72f:20ad:e1b6 with SMTP id sd29-20020a1709076e1d00b0072f20ade1b6mr21346463ejc.545.1659547727748; Wed, 03 Aug 2022 10:28:47 -0700 (PDT) MIME-Version: 1.0 References: <20220606103734.92423-1-kurt@linutronix.de> <875ylc6djv.ffs@tglx> <87pmhj15vf.fsf@kurt> <87edxxg7qu.fsf@kurt> In-Reply-To: <87edxxg7qu.fsf@kurt> From: Andrii Nakryiko Date: Wed, 3 Aug 2022 10:28:36 -0700 Message-ID: Subject: Re: [PATCH bpf-next] bpf: Add BPF-helper for accessing CLOCK_TAI To: Kurt Kanzenbach Cc: Alexei Starovoitov , Jesper Dangaard Brouer , Thomas Gleixner , Jesper Dangaard Brouer , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , Joanne Koong , Jiri Olsa , Dave Marchevsky , Lorenzo Bianconi , Geliang Tang , Jakub Sitnicki , Network Development , bpf Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On Tue, Aug 2, 2022 at 11:29 PM Kurt Kanzenbach wrote: > > On Tue Aug 02 2022, Alexei Starovoitov wrote: > > On Tue, Aug 2, 2022 at 12:06 AM Kurt Kanzenbach wrote: > >> > >> Hi Alexei, > >> > >> On Tue Jun 07 2022, Alexei Starovoitov wrote: > >> > Anyway I guess new helper bpf_ktime_get_tai_ns() is ok, since > >> > it's so trivial, but selftest is necessary. > >> > >> So, I did write a selftest [1] for testing bpf_ktime_get_tai_ns() and > >> verifying that the access to the clock works. It uses AF_XDP sockets and > >> timestamps the incoming packets. The timestamps are then validated in > >> user space. > >> > >> Since AF_XDP related code is migrating from libbpf to libxdp, I'm > >> wondering if that sample fits into the kernel's selftests or not. What > >> kind of selftest are you looking for? > > > > Please use selftests/bpf framework. > > There are plenty of networking tests in there. > > bpf_ktime_get_tai_ns() doesn't have to rely on af_xdp. > > OK. > > > It can be skb based. > > Something like this? > > +++ b/tools/testing/selftests/bpf/prog_tests/check_tai.c > @@ -0,0 +1,57 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* Copyright (C) 2022 Linutronix GmbH */ > + > +#include > +#include > + > +#include > +#include > + > +#define TAI_THRESHOLD 1000000000ULL /* 1s */ > +#define NSEC_PER_SEC 1000000000ULL > + > +static __u64 ts_to_ns(const struct timespec *ts) > +{ > + return ts->tv_sec * NSEC_PER_SEC + ts->tv_nsec; > +} > + > +void test_tai(void) > +{ > + struct __sk_buff skb = { > + .tstamp = 0, > + .hwtstamp = 0, > + }; > + LIBBPF_OPTS(bpf_test_run_opts, topts, > + .data_in = &pkt_v4, > + .data_size_in = sizeof(pkt_v4), > + .ctx_in = &skb, > + .ctx_size_in = sizeof(skb), > + .ctx_out = &skb, > + .ctx_size_out = sizeof(skb), > + ); > + struct timespec now_tai; > + struct bpf_object *obj; > + int ret, prog_fd; > + > + ret = bpf_prog_test_load("./test_tai.o", > + BPF_PROG_TYPE_SCHED_CLS, &obj, &prog_fd); it would be best to rely on BPF skeleton, please see other tests including *.skel.h, thanks > + if (!ASSERT_OK(ret, "load")) > + return; > + ret = bpf_prog_test_run_opts(prog_fd, &topts); > + ASSERT_OK(ret, "test_run"); > + > + /* TAI != 0 */ > + ASSERT_NEQ(skb.tstamp, 0, "tai_ts0_0"); > + ASSERT_NEQ(skb.hwtstamp, 0, "tai_ts0_1"); > + > + /* TAI is moving forward only */ > + ASSERT_GT(skb.hwtstamp, skb.tstamp, "tai_forward"); > + > + /* Check for reasoneable range */ > + ret = clock_gettime(CLOCK_TAI, &now_tai); > + ASSERT_EQ(ret, 0, "tai_gettime"); > + ASSERT_TRUE((ts_to_ns(&now_tai) - skb.hwtstamp) < TAI_THRESHOLD, > + "tai_range"); > + > + bpf_object__close(obj); > +} > diff --git a/tools/testing/selftests/bpf/progs/test_tai.c b/tools/testing/selftests/bpf/progs/test_tai.c > new file mode 100644 > index 000000000000..34ac4175e29d > --- /dev/null > +++ b/tools/testing/selftests/bpf/progs/test_tai.c > @@ -0,0 +1,17 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* Copyright (C) 2022 Linutronix GmbH */ > + > +#include > +#include > + > +char _license[] SEC("license") = "GPL"; > + > +SEC("tc") > +int save_tai(struct __sk_buff *skb) > +{ > + /* Save TAI timestamps */ > + skb->tstamp = bpf_ktime_get_tai_ns(); > + skb->hwtstamp = bpf_ktime_get_tai_ns(); > + > + return 0; > +}