From nobody Thu Apr 16 15:28:26 2026 X-Original-To: dev-commits-src-all@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id 4fxMNX5bzgz6ZrF6 for ; Thu, 16 Apr 2026 15:28:28 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "R12" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id 4fxMNV72Q2z3Fxs for ; Thu, 16 Apr 2026 15:28:26 +0000 (UTC) (envelope-from git@FreeBSD.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1776353307; h=from:from: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; bh=RHZ4qWUX6HJtmwCYy/Dvn/F0/BCaLh5YNvLaSqALMpc=; b=grXEjrth1XSYh9RjPMxe/2h74Paoumfzae86ar5t2KRtbdUjit8ZQv9XsKI3akKdgw3R3v cnlH6Fzymf+KKa2xsKizMgV7anTtxCOc1Jgm2+GOjy7igcO3ynqNxPhr4r3dcryXv8NrJk BtsGVrj+NACk4TzMwsxEWpATB8YPOp1njjFdl1lwFYHrIOuiQUYgJ3VydyI6o0yKESRj/3 0A3kvsEmJ1/Mif+gSJX8XZRRZtKngyOGYHZBT69hMXPsjqAPwYPO/jEXgxWKwuhRd8P56r BPZR3EN7a4tXrTkiodUrwPkA3OAhieUnSvlqQNXOho/llWje6REjK63x71usxg== ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1776353307; a=rsa-sha256; cv=none; b=pDgv4g+Ts+Vl774+5kzo5j1V5OzMtXWmcSWTZyGPm3L7wD4bkWJY5UpvBLI7e0mXt4ZYbK v89YwfJRURVAHoltZgO36wrgIFRlpTNDu5qYr0RB0wP/G/s542TsK4ELp2+L+hyGawcZwN MRshJSShL1G+KBWYERk4gfZMRM5wZwtDp2qY96tybbqf+95CZUQ6gyBAROn5O9Rz6Sfq5U Ve4GgIn+T/Wt4eY4ZO9UL7L6MsXFzi0P5iB9x0ZYf69IH7iWAeAv5APmR5GCC+r9mm23mE 2oBUMQ35k1yT1RfXDdnYalPB2cKxNshM/K9X5YdHkzddmMFpH2Ffu23Frz6wAw== ARC-Authentication-Results: i=1; mx1.freebsd.org; none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1776353307; h=from:from: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; bh=RHZ4qWUX6HJtmwCYy/Dvn/F0/BCaLh5YNvLaSqALMpc=; b=UjpsvI31GmhhBYOkZgfZWWiEKpcLMC4AslRS+/CXzbvI9gKmqpSEbowjpwmbhBVyFzTvvK WQFY2S+8Z0IqDsrmumtHZnN1pxSYAQOF23b8nS9/FBQvdR8QagyK4qZdF3Z5rpa+LlNVVP 0uIs9CX05ahTmnEulxte425oaZT0mKIL7yrmi1llLDDr9ohGoeY034YVyFQQfEeK6y4At0 vlAps8oQIeqh1sk5FveVqhsSV1qySUGn8O3DVB/rAQC5/z86DnakNkszZR1pHOSFf/cW9t 6CDqWzZwTJFjqXuK6//NTmaAuuBs9f43psqiI8I+TT7c9Et80l3+a0m15GzGBg== Received: from gitrepo.freebsd.org (gitrepo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:5]) by mxrelay.nyi.freebsd.org (Postfix) with ESMTP id 4fxMNV6Z6sz1Bkm for ; Thu, 16 Apr 2026 15:28:26 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from git (uid 1279) (envelope-from git@FreeBSD.org) id 1ebdc by gitrepo.freebsd.org (DragonFly Mail Agent v0.13+ on gitrepo.freebsd.org); Thu, 16 Apr 2026 15:28:26 +0000 To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org Cc: Ali Mashtizadeh From: Mitchell Horne Subject: git: f72a16118608 - stable/15 - hwpmc: Use rdtsc instead of rdtscp for timestamps List-Id: Commit messages for all branches of the src repository List-Archive: https://lists.freebsd.org/archives/dev-commits-src-all List-Help: List-Post: List-Subscribe: List-Unsubscribe: X-BeenThere: dev-commits-src-all@freebsd.org Sender: owner-dev-commits-src-all@FreeBSD.org MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Git-Committer: mhorne X-Git-Repository: src X-Git-Refname: refs/heads/stable/15 X-Git-Reftype: branch X-Git-Commit: f72a161186084f170de8ace22722e848cb1073fa Auto-Submitted: auto-generated Date: Thu, 16 Apr 2026 15:28:26 +0000 Message-Id: <69e1001a.1ebdc.3682fc90@gitrepo.freebsd.org> The branch stable/15 has been updated by mhorne: URL: https://cgit.FreeBSD.org/src/commit/?id=f72a161186084f170de8ace22722e848cb1073fa commit f72a161186084f170de8ace22722e848cb1073fa Author: Ali Mashtizadeh AuthorDate: 2026-03-23 20:21:21 +0000 Commit: Mitchell Horne CommitDate: 2026-04-16 15:18:24 +0000 hwpmc: Use rdtsc instead of rdtscp for timestamps No need for a barrier here, we are inside an NMI handler and executing a number of serializing instructions with stronger semantics. Reducing this overhead will increase our maximum safe sampling rate. Tested by: Paulo Fragoso Reviewed by: mhorne MFC after: 1 week Sponsored by: Netflix Pull Request: https://github.com/freebsd/freebsd-src/pull/2076 (cherry picked from commit 39515d8b623a2be39d0c42a537fd9a17c417ff6e) --- sys/dev/hwpmc/hwpmc_mod.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) diff --git a/sys/dev/hwpmc/hwpmc_mod.c b/sys/dev/hwpmc/hwpmc_mod.c index a6a6ae68996c..04e23ae24c31 100644 --- a/sys/dev/hwpmc/hwpmc_mod.c +++ b/sys/dev/hwpmc/hwpmc_mod.c @@ -812,11 +812,9 @@ pmc_force_context_switch(void) uint64_t pmc_rdtsc(void) { -#if defined(__i386__) || defined(__amd64__) - if (__predict_true(amd_feature & AMDID_RDTSCP)) - return (rdtscp()); - else - return (rdtsc()); +#if defined(__i386__) + /* Unfortunately get_cyclecount on i386 uses cpu_ticks. */ + return (rdtsc()); #else return (get_cyclecount()); #endif