From nobody Tue Dec 21 10:56:35 2021 X-Original-To: bugs@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 6F78F1904B13 for ; Tue, 21 Dec 2021 10:56:35 +0000 (UTC) (envelope-from bugzilla-noreply@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 "R3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4JJD0g24pGz4jRn for ; Tue, 21 Dec 2021 10:56:35 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org (kenobi.freebsd.org [IPv6:2610:1c1:1:606c::50:1d]) (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 did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 2450D4BA for ; Tue, 21 Dec 2021 10:56:35 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org ([127.0.1.5]) by kenobi.freebsd.org (8.15.2/8.15.2) with ESMTP id 1BLAuZMq087034 for ; Tue, 21 Dec 2021 10:56:35 GMT (envelope-from bugzilla-noreply@freebsd.org) Received: (from www@localhost) by kenobi.freebsd.org (8.15.2/8.15.2/Submit) id 1BLAuZBp087033 for bugs@FreeBSD.org; Tue, 21 Dec 2021 10:56:35 GMT (envelope-from bugzilla-noreply@freebsd.org) X-Authentication-Warning: kenobi.freebsd.org: www set sender to bugzilla-noreply@freebsd.org using -f From: bugzilla-noreply@freebsd.org To: bugs@FreeBSD.org Subject: [Bug 254040] AMD 5950X hyperthreading strange performance swings Date: Tue, 21 Dec 2021 10:56:35 +0000 X-Bugzilla-Reason: AssignedTo X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: Base System X-Bugzilla-Component: kern X-Bugzilla-Version: 12.2-RELEASE X-Bugzilla-Keywords: X-Bugzilla-Severity: Affects Some People X-Bugzilla-Who: avg@FreeBSD.org X-Bugzilla-Status: New X-Bugzilla-Resolution: X-Bugzilla-Priority: --- X-Bugzilla-Assigned-To: bugs@FreeBSD.org X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: https://bugs.freebsd.org/bugzilla/ Auto-Submitted: auto-generated List-Id: Bug reports List-Archive: https://lists.freebsd.org/archives/freebsd-bugs List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-freebsd-bugs@freebsd.org MIME-Version: 1.0 ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1640084195; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=DrJS9XGu2FiGnBN1GlyF3yuRJ3lCQivI2BzHcvo1Iac=; b=v0CMf18TowWOC7Rmk2ShLPcCnPQ50zrwW/bMxOTBi7qht2NLf3uvHOhQksBlXJwn+lsTA7 t/jSP9CW4bK/GdQUH+UC6h1Utal0f+daZuU9jDqrDYpHRwMrgYd64ZfbMyH84ZTKTENhIt M3dy55f+msQgtPaW1z/ZkIG8OLfk3aLNhytVOj/T9bx7rdeKT9BkjaGpvFOSqCPlvlPa0i n7/LaZzQJRDcuwU90mgcgizRcPBlNZYK7yvFKtjqhg8FJGcJbmN215hCiKSY865q8Ui2YM +5qIp1Zu092VbImTMzLFOwiz+QuXGtOYeEcDxFmViPP7hsCsmy4WLmfNCsS4fQ== ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1640084195; a=rsa-sha256; cv=none; b=aMvLfhrxbvVAB3hHSGrrwxlxYRPdis2O56FHargFWfLEb7PNs+2b9ASTf6ijUU+h6klJgn zHJEPmpYf7ymeIivHgp7MoL0RQCvrjg2Uw7Kr9QF48RjtiRn8ZfpLDBAqcdTUWZsUpL9DJ 8M4j6hjUpw5IyHIY/a8WcPdR8uiCiCBLBQHaOYx5kgu4gWWtxCn8V7O1pfzG2Ow+vZW9T3 qm9Lu/CfhAmCjMAQOIvH4YJev2o4GZB9WFteEm+pvpA5o8rD8jD+exDiP5dllFaNPsLU09 2qI5GZN+v6xsLu6gnT3MumUQIl0S3gewNsaxYHLhMC266xlDA88OSN+DsLkR6g== ARC-Authentication-Results: i=1; mx1.freebsd.org; none X-ThisMailContainsUnwantedMimeParts: N https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D254040 --- Comment #5 from Andriy Gapon --- And a possible "eureka moment" that's consistent with the original descript= ion: if I choose odd logical CPUs, (cpuset -l $((2 * i + 1)), then I consistently get the worst results: $ ~/test.sh 4 1048576000 bytes transferred in 7.800822 secs (134418651 bytes/sec) 1048576000 bytes transferred in 7.803095 secs (134379498 bytes/sec) 1048576000 bytes transferred in 7.809778 secs (134264513 bytes/sec) 1048576000 bytes transferred in 7.810560 secs (134251064 bytes/sec) If this is indeed what it is, then several conclusions can be drawn: - hardware threads within a core are not born equal on this hardware - "primary" threads should be preferred - ULE does not do that --=20 You are receiving this mail because: You are the assignee for the bug.=