From nobody Mon Mar 23 20:22:14 2026 X-Original-To: dev-commits-src-main@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 4ffl2Z4K7kz6WSqG for ; Mon, 23 Mar 2026 20:22:14 +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 4ffl2Z37qKz3VVd for ; Mon, 23 Mar 2026 20:22:14 +0000 (UTC) (envelope-from git@FreeBSD.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1774297334; 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=SwJpx8FUTMfkcyW9I4iX+9H9MFeVJWyF/xW1lcccQUU=; b=dGwiOUWXYqgb8+VnJEQHp7isGjuuqRXf28c07RWGF9x8awEswiCPhDvoWne4IPBBuVeFDh KHtkFlVy4M5Hi2vK1EhE4zLyGT2SBQywUdwymhBjgPG0i3OntyJbfYZc0xXND6YqrEQ/Jp kQzRpfY0GZx649lSD3VRr8tDPNwHa9Qa2GvrbtPgHMifo/bse5crh1fJBWQzhJ6aggL8t/ fqwzhRqK14gx7XuDVgTumJ0H7n/qlCmi51gYWhyHCbgfAV5jCKh8KfyTL60YIeKTJb2o92 njlFkm/cXkN8lrE8mzyhLrYezSiTH//Bb+x54jFdiC1IbC9x/dBsIMJ7xK1aVg== ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1774297334; a=rsa-sha256; cv=none; b=NecdC+yAbWZWau64zNRj1RY2OGz99W0NKuOiBqgCdnIhxV5bjVLWNjx7wIGkLr2YWgxw/G x/GNXwVq9rcvJVeCxfH9cKRc+uuN6+HZ1MW+MVeOMT84pKu0WgLqWW7QEzZGe5nZj0wvT1 GEP98DqZPvViZZ9EXHd9uOpdwKN2cXuC4ABoIZs0Yf3O91n9AOwWZM4dIJx3fa5pSgtimf WgjWrngX0JY8t6KV9U8pxqxRzyTZwDu0aJ4RntLNnQYY+LxxHklI714Sln8TQXBocR76Yh LuxuGK2Ras/nZMY7fMuzl5wgAz/OepQ/RxqaUQx/pX7aeGwX0NUYk6QkAPMB+w== 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=1774297334; 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=SwJpx8FUTMfkcyW9I4iX+9H9MFeVJWyF/xW1lcccQUU=; b=O9CUG+2+JtEhGR1N+cePHAUS4X+tCL9FVufRM+iJnetGx3C7B+nCA7b8ZhWioXfTry+axl lUnU3YWC9vvMcdNnjrzoMAG1fKL0kKt7ueKAsai6LT/tIhHBObdwTJj6VI9MqKVwBU1+SB Z8rh3YTHm7opmCxoYNCk14SqPtNAKXYd9F4zHFVUETIXzE9fodkaGuEix2wMrrZJsPlkiR Mmw0SrTLD8ljfUI3Ko4orj8ipxLIslSPig9ZHc6zuX2xBQ8lgKHAoZUkW65deiQJc2ka2a M5epXkNncAVoi7/7FudGZ/+XoK+vn9uuWW6I9jW8gTJ6kvC7EU8B0AkFuHm8oQ== Received: from gitrepo.freebsd.org (gitrepo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:5]) by mxrelay.nyi.freebsd.org (Postfix) with ESMTP id 4ffl2Z2cMzz13fT for ; Mon, 23 Mar 2026 20:22:14 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from git (uid 1279) (envelope-from git@FreeBSD.org) id 18dce by gitrepo.freebsd.org (DragonFly Mail Agent v0.13+ on gitrepo.freebsd.org); Mon, 23 Mar 2026 20:22:14 +0000 To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Cc: Ali Mashtizadeh From: Mitchell Horne Subject: git: 39515d8b623a - main - hwpmc: Use rdtsc instead of rdtscp for timestamps List-Id: Commit messages for the main branch of the src repository List-Archive: https://lists.freebsd.org/archives/dev-commits-src-main List-Help: List-Post: List-Subscribe: List-Unsubscribe: X-BeenThere: dev-commits-src-main@freebsd.org Sender: owner-dev-commits-src-main@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/main X-Git-Reftype: branch X-Git-Commit: 39515d8b623a2be39d0c42a537fd9a17c417ff6e Auto-Submitted: auto-generated Date: Mon, 23 Mar 2026 20:22:14 +0000 Message-Id: <69c1a0f6.18dce.494c23c4@gitrepo.freebsd.org> The branch main has been updated by mhorne: URL: https://cgit.FreeBSD.org/src/commit/?id=39515d8b623a2be39d0c42a537fd9a17c417ff6e commit 39515d8b623a2be39d0c42a537fd9a17c417ff6e Author: Ali Mashtizadeh AuthorDate: 2026-03-23 20:21:21 +0000 Commit: Mitchell Horne CommitDate: 2026-03-23 20:21:21 +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 --- 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 fb1fdf832398..6133b52b516f 100644 --- a/sys/dev/hwpmc/hwpmc_mod.c +++ b/sys/dev/hwpmc/hwpmc_mod.c @@ -818,11 +818,9 @@ 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