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 9C323C77B75 for ; Tue, 18 Apr 2023 14:53:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232037AbjDROxr (ORCPT ); Tue, 18 Apr 2023 10:53:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49930 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230138AbjDROxd (ORCPT ); Tue, 18 Apr 2023 10:53:33 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4AE38C678; Tue, 18 Apr 2023 07:53:29 -0700 (PDT) Date: Tue, 18 Apr 2023 14:53:27 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1681829608; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=6ITfUbOfV2vztKvWzmFN8WZkFvcN10ekh69DY+h23qs=; b=fBNDk/Fsjwlf/NZsXb9obBKndRsWYCVqjUeikpryrG4aJ324vw90Ie3ENAclS1fpsbhVMk dxRSWDkSyPpiMpXHlzvirwolVVP8GJ6eWx6WJ7m1dumoo1g38uy81Q28mVAGsicFD30J2g KWeZfduuP9hyZn+MRLyii1WlDadCcoN345AXXxAnfEkrx0sw1k4lEnFGNYiAI+1wiNRHhb ncmyoUVtA+p2cNTSKZmP9nobjhRLWjiwlMv2c/+Mbr7jkpVEdcvL4gUkhzCQUdbabngnzU qn8SJV/Y8XW03WAHUqzZBNXApxSTpZzwcSQHHRcn26qkcwAAfdmjQEg576uriQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1681829608; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=6ITfUbOfV2vztKvWzmFN8WZkFvcN10ekh69DY+h23qs=; b=7SHOyDkmtBEh1w/+U4WZzK47qGmLl5xwOLIMuX9js/XSXCOkRCLVGxjL5gyr/2+DJewgUi 62xjWC6d5BRYJkDw== From: "tip-bot2 for Frederic Weisbecker" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: timers/core] selftests/proc: Remove idle time monotonicity assertions Cc: Yu Liao , Thomas Gleixner , Frederic Weisbecker , x86@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <20230222144649.624380-8-frederic@kernel.org> References: <20230222144649.624380-8-frederic@kernel.org> MIME-Version: 1.0 Message-ID: <168182960780.404.14266363355054554836.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the timers/core branch of tip: Commit-ID: 270b2a679ea7be1ee2d84ea67751fb1ab15bcb20 Gitweb: https://git.kernel.org/tip/270b2a679ea7be1ee2d84ea67751fb1ab15bcb20 Author: Frederic Weisbecker AuthorDate: Wed, 22 Feb 2023 15:46:48 +01:00 Committer: Thomas Gleixner CommitterDate: Tue, 18 Apr 2023 16:35:13 +02:00 selftests/proc: Remove idle time monotonicity assertions Due to broken iowait task counting design (cf: comments above get_cpu_idle_time_us() and nr_iowait()), it is not possible to provide the guarantee that /proc/stat or /proc/uptime display monotonic idle time values. Remove the assertions that verify the related wrong assumption so that testers and maintainers don't spend more time on that. Reported-by: Yu Liao Reported-by: Thomas Gleixner Signed-off-by: Frederic Weisbecker Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/r/20230222144649.624380-8-frederic@kernel.org --- tools/testing/selftests/proc/proc-uptime-001.c | 12 ++++++------ tools/testing/selftests/proc/proc-uptime-002.c | 13 ++++++------- tools/testing/selftests/proc/proc-uptime.h | 16 ++-------------- 3 files changed, 14 insertions(+), 27 deletions(-) diff --git a/tools/testing/selftests/proc/proc-uptime-001.c b/tools/testing/selftests/proc/proc-uptime-001.c index 781f7a5..35bddd9 100644 --- a/tools/testing/selftests/proc/proc-uptime-001.c +++ b/tools/testing/selftests/proc/proc-uptime-001.c @@ -13,7 +13,9 @@ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ -// Test that values in /proc/uptime increment monotonically. +// Test that boottime value in /proc/uptime increments monotonically. +// We don't test idle time monotonicity due to broken iowait task +// counting, cf: comment above get_cpu_idle_time_us() #undef NDEBUG #include #include @@ -25,20 +27,18 @@ int main(void) { - uint64_t start, u0, u1, i0, i1; + uint64_t start, u0, u1; int fd; fd = open("/proc/uptime", O_RDONLY); assert(fd >= 0); - proc_uptime(fd, &u0, &i0); + u0 = proc_uptime(fd); start = u0; do { - proc_uptime(fd, &u1, &i1); + u1 = proc_uptime(fd); assert(u1 >= u0); - assert(i1 >= i0); u0 = u1; - i0 = i1; } while (u1 - start < 100); return 0; diff --git a/tools/testing/selftests/proc/proc-uptime-002.c b/tools/testing/selftests/proc/proc-uptime-002.c index 7d0aa22..7ad79d5 100644 --- a/tools/testing/selftests/proc/proc-uptime-002.c +++ b/tools/testing/selftests/proc/proc-uptime-002.c @@ -13,8 +13,9 @@ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ -// Test that values in /proc/uptime increment monotonically -// while shifting across CPUs. +// Test that boottime value in /proc/uptime increments monotonically +// while shifting across CPUs. We don't test idle time monotonicity +// due to broken iowait task counting, cf: comment above get_cpu_idle_time_us() #undef NDEBUG #include #include @@ -45,7 +46,7 @@ int main(void) unsigned int len; unsigned long *m; unsigned int cpu; - uint64_t u0, u1, i0, i1; + uint64_t u0, u1; int fd; /* find out "nr_cpu_ids" */ @@ -60,7 +61,7 @@ int main(void) fd = open("/proc/uptime", O_RDONLY); assert(fd >= 0); - proc_uptime(fd, &u0, &i0); + u0 = proc_uptime(fd); for (cpu = 0; cpu < len * 8; cpu++) { memset(m, 0, len); m[cpu / (8 * sizeof(unsigned long))] |= 1UL << (cpu % (8 * sizeof(unsigned long))); @@ -68,11 +69,9 @@ int main(void) /* CPU might not exist, ignore error */ sys_sched_setaffinity(0, len, m); - proc_uptime(fd, &u1, &i1); + u1 = proc_uptime(fd); assert(u1 >= u0); - assert(i1 >= i0); u0 = u1; - i0 = i1; } return 0; diff --git a/tools/testing/selftests/proc/proc-uptime.h b/tools/testing/selftests/proc/proc-uptime.h index dc6a42b..ca55abe 100644 --- a/tools/testing/selftests/proc/proc-uptime.h +++ b/tools/testing/selftests/proc/proc-uptime.h @@ -22,7 +22,7 @@ #include "proc.h" -static void proc_uptime(int fd, uint64_t *uptime, uint64_t *idle) +static uint64_t proc_uptime(int fd) { uint64_t val1, val2; char buf[64], *p; @@ -43,18 +43,6 @@ static void proc_uptime(int fd, uint64_t *uptime, uint64_t *idle) assert(p[3] == ' '); val2 = (p[1] - '0') * 10 + p[2] - '0'; - *uptime = val1 * 100 + val2; - p += 4; - - val1 = xstrtoull(p, &p); - assert(p[0] == '.'); - assert('0' <= p[1] && p[1] <= '9'); - assert('0' <= p[2] && p[2] <= '9'); - assert(p[3] == '\n'); - - val2 = (p[1] - '0') * 10 + p[2] - '0'; - *idle = val1 * 100 + val2; - - assert(p + 4 == buf + rv); + return val1 * 100 + val2; }