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 mails.dpdk.org (mails.dpdk.org [217.70.189.124]) by smtp.lore.kernel.org (Postfix) with ESMTP id 11FE1D6CFA2 for ; Thu, 22 Jan 2026 18:03:49 +0000 (UTC) Received: from mails.dpdk.org (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id B325C4027A; Thu, 22 Jan 2026 19:03:48 +0100 (CET) Received: from inbox.dpdk.org (inbox.dpdk.org [95.142.172.178]) by mails.dpdk.org (Postfix) with ESMTP id 799F040274 for ; Thu, 22 Jan 2026 19:03:47 +0100 (CET) Received: by inbox.dpdk.org (Postfix, from userid 33) id 507AF4A2AF; Thu, 22 Jan 2026 19:03:47 +0100 (CET) From: bugzilla@dpdk.org To: dev@dpdk.org Subject: [DPDK/core Bug 1869] incorrect get_tsc_freq_arch() due to integer truncation Date: Thu, 22 Jan 2026 18:03:47 +0000 X-Bugzilla-Reason: AssignedTo X-Bugzilla-Type: new X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: DPDK X-Bugzilla-Component: core X-Bugzilla-Version: unspecified X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: rizzo.unipi@gmail.com X-Bugzilla-Status: UNCONFIRMED X-Bugzilla-Resolution: X-Bugzilla-Priority: Normal X-Bugzilla-Assigned-To: dev@dpdk.org X-Bugzilla-Target-Milestone: --- X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: bug_id short_desc product version rep_platform op_sys bug_status bug_severity priority component assigned_to reporter target_milestone Message-ID: Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=UTF-8 X-Bugzilla-URL: http://bugs.dpdk.org/ Auto-Submitted: auto-generated X-Auto-Response-Suppress: All MIME-Version: 1.0 X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org http://bugs.dpdk.org/show_bug.cgi?id=3D1869 Bug ID: 1869 Summary: incorrect get_tsc_freq_arch() due to integer truncation Product: DPDK Version: unspecified Hardware: x86 OS: All Status: UNCONFIRMED Severity: normal Priority: Normal Component: core Assignee: dev@dpdk.org Reporter: rizzo.unipi@gmail.com Target Milestone: --- There is a bug in https://github.com/DPDK/dpdk/blob/main/lib/eal/x86/rte_cycles.c#L148 143 __cpuid(0x15, a, b, c, d);=20=20 ... 146 /* EBX : TSC/Crystal ratio, ECX : Crystal Hz */ 147 if (b && c) 148 return c * (b / a); On one machine, line 143 returns a 10 b 23 c 1000000000 d 0, the division (b / a) returns 2 hence leading to an incorrect value (2 GHz instead of 2.3 GHz) The trivial fix is to replace line 148 with return (uint64_t)c * b / a; --=20 You are receiving this mail because: You are the assignee for the bug.=