From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hugh Dickins Subject: Re: [PATCH V4 0/2] mm: FAULT_AROUND_ORDER patchset performance data for powerpc Date: Mon, 19 May 2014 19:34:27 -0700 (PDT) Message-ID: References: <1399541296-18810-1-git-send-email-maddy@linux.vnet.ibm.com> <537479E7.90806@linux.vnet.ibm.com> <87wqdik4n5.fsf@rustcorp.com.au> <53797511.1050409@linux.vnet.ibm.com> <87d2f9jlpd.fsf@rustcorp.com.au> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Return-path: In-Reply-To: <87d2f9jlpd.fsf@rustcorp.com.au> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linuxppc-dev-bounces+glppe-linuxppc-embedded-2=m.gmane.org@lists.ozlabs.org Sender: "Linuxppc-dev" To: Rusty Russell Cc: linux-arch@vger.kernel.org, riel@redhat.com, Madhavan Srinivasan , dave.hansen@intel.com, peterz@infradead.org, x86@kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, ak@linux.intel.com, paulus@samba.org, mgorman@suse.de, akpm@linux-foundation.org, linuxppc-dev@lists.ozlabs.org, mingo@kernel.org, "Kirill A. Shutemov" List-Id: linux-arch.vger.kernel.org T24gVHVlLCAyMCBNYXkgMjAxNCwgUnVzdHkgUnVzc2VsbCB3cm90ZToKPiBIdWdoIERpY2tpbnMg PGh1Z2hkQGdvb2dsZS5jb20+IHdyaXRlczoKPiA+PiBPbiBNb25kYXkgMTkgTWF5IDIwMTQgMDU6 NDIgQU0sIFJ1c3R5IFJ1c3NlbGwgd3JvdGU6Cj4gPj4gPiAKPiA+PiA+IFBlcmhhcHMgd2UgdHJ5 IHRvIGdlbmVyYWxpemUgZnJvbSB0d28gZGF0YSBwb2ludHMgKGEgc2xpZ2h0IGltcHJvdmVtZW50 Cj4gPj4gPiBvdmVyIGRvaW5nIGl0IGZyb20gMSEpLCBlZzoKPiA+PiA+IAo+ID4+ID4gLyogNCBz ZWVtcyBnb29kIGZvciA0ay1wYWdlIHg4NiwgMCBzZWVtcyBnb29kIGZvciA2NGsgcGFnZSBwcGM2 NCwgc286ICovCj4gPj4gPiB1bnNpZ25lZCBpbnQgZmF1bHRfYXJvdW5kX29yZGVyIF9fcmVhZF9t b3N0bHkgPQo+ID4+ID4gICAgICAgICAoMTYgLSBQQUdFX1NISUZUIDwgMCA/IDAgOiAxNiAtIFBB R0VfU0hJRlQpOwo+ID4KPiA+IFJ1c3R5J3MgYmltb2RhbCBhbnN3ZXIgZG9lc24ndCBzZWVtIHRo ZSByaWdodCBzdGFydGluZyBwb2ludCB0byBtZS4KPiAKPiA/ICBJdCdzIG5vdCBiaW1vZGFsLCBp dCdzIGdyYWRlZC4gIEkgdGhpbmsgeW91IG1pc3JlYWQ/CgpZaWtlcywgd29yc2UgdGhhbiBtaXNy ZWFkLCBtb3JlIGxpa2UgSSB3YXMgdG9vIHJ1ZGUgZXZlbiB0byByZWFkOiBzb3JyeSEKCkh1Z2gK X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX18KTGludXhwcGMt ZGV2IG1haWxpbmcgbGlzdApMaW51eHBwYy1kZXZAbGlzdHMub3psYWJzLm9yZwpodHRwczovL2xp c3RzLm96bGFicy5vcmcvbGlzdGluZm8vbGludXhwcGMtZGV2 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pb0-f44.google.com ([209.85.160.44]:47666 "EHLO mail-pb0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751515AbaETCfo (ORCPT ); Mon, 19 May 2014 22:35:44 -0400 Received: by mail-pb0-f44.google.com with SMTP id rq2so6590115pbb.31 for ; Mon, 19 May 2014 19:35:44 -0700 (PDT) Date: Mon, 19 May 2014 19:34:27 -0700 (PDT) From: Hugh Dickins Subject: Re: [PATCH V4 0/2] mm: FAULT_AROUND_ORDER patchset performance data for powerpc In-Reply-To: <87d2f9jlpd.fsf@rustcorp.com.au> Message-ID: References: <1399541296-18810-1-git-send-email-maddy@linux.vnet.ibm.com> <537479E7.90806@linux.vnet.ibm.com> <87wqdik4n5.fsf@rustcorp.com.au> <53797511.1050409@linux.vnet.ibm.com> <87d2f9jlpd.fsf@rustcorp.com.au> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-arch-owner@vger.kernel.org List-ID: To: Rusty Russell Cc: Madhavan Srinivasan , "Kirill A. Shutemov" , linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, x86@kernel.org, benh@kernel.crashing.org, paulus@samba.org, akpm@linux-foundation.org, riel@redhat.com, mgorman@suse.de, ak@linux.intel.com, peterz@infradead.org, mingo@kernel.org, dave.hansen@intel.com Message-ID: <20140520023427.HTLw4DCHhvW2IPLw-HE4kcxMbh1uKvOQ5BXpndg3CXM@z> On Tue, 20 May 2014, Rusty Russell wrote: > Hugh Dickins writes: > >> On Monday 19 May 2014 05:42 AM, Rusty Russell wrote: > >> > > >> > Perhaps we try to generalize from two data points (a slight improvement > >> > over doing it from 1!), eg: > >> > > >> > /* 4 seems good for 4k-page x86, 0 seems good for 64k page ppc64, so: */ > >> > unsigned int fault_around_order __read_mostly = > >> > (16 - PAGE_SHIFT < 0 ? 0 : 16 - PAGE_SHIFT); > > > > Rusty's bimodal answer doesn't seem the right starting point to me. > > ? It's not bimodal, it's graded. I think you misread? Yikes, worse than misread, more like I was too rude even to read: sorry! Hugh