From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by sourceware.org (Postfix) with ESMTPS id 91D783858D33 for ; Tue, 8 Aug 2023 03:38:35 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 91D783858D33 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=redhat.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1691465915; 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: in-reply-to:in-reply-to; bh=VtngI89yDhLgURExbDwfa8qefFUcH8EC7jHjFA7SVys=; b=ini86uSydb9epBScy5RHjcuhditKKK796n1EATUXJJLOQLXft7IsqLzy8z6C2BqNqmobuP f1B5zMUmm8wGjDV60Y6CnBlBV2wdQ2yY1ad776GMjijyfq6wQBsDIQr6pqxxFbQKPqPNyN IKve+U93b17x2r8EqWnnRYrWsYaaNlE= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-437-hnpnjvR0OLmiDWdhKCxJDg-1; Mon, 07 Aug 2023 23:38:29 -0400 X-MC-Unique: hnpnjvR0OLmiDWdhKCxJDg-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 46B76858290; Tue, 8 Aug 2023 03:38:29 +0000 (UTC) Received: from greed.delorie.com (unknown [10.22.8.85]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 09AD740C6F4E; Tue, 8 Aug 2023 03:38:28 +0000 (UTC) Received: from greed.delorie.com.redhat.com (localhost [127.0.0.1]) by greed.delorie.com (8.15.2/8.15.2) with ESMTP id 3783cRda2332691; Mon, 7 Aug 2023 23:38:27 -0400 From: DJ Delorie To: Sam James Cc: adhemerval.zanella@linaro.org, xry111@xry111.site, libc-alpha@sourceware.org, dilfridge@gentoo.org, timo@rothenpieler.org Subject: Re: posix_memalign performance regression in 2.38? In-Reply-To: <878ramtybs.fsf@gentoo.org> (message from Sam James on Mon, 07 Aug 2023 20:57:26 +0100) Date: Mon, 07 Aug 2023 23:38:27 -0400 Message-ID: MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.2 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain X-Spam-Status: No, score=-4.4 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE,RCVD_IN_MSPIKE_H4,RCVD_IN_MSPIKE_WL,SPF_HELO_NONE,SPF_NONE,TXREP autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: Reproduced. In the case where I reproduced it, the most common problematic case was an allocation of 64-byte aligned chunks of 472 bytes, where 30 smallbin chunks were tested without finding a match. The most common non-problematic case was a 64-byte-aligned request for 24 bytes. There were a LOT of other size requests. The smallest I saw was TWO bytes. WHY? I'm tempted to not fix this, to teach developers to not use posix_memalign() unless they REALLY need it ;-)