From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3rLZnC11XPzDqkr for ; Fri, 3 Jun 2016 17:03:26 +1000 (AEST) Received: from pps.filterd (m0048827.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.11/8.16.0.11) with SMTP id u5370RXD035331 for ; Fri, 3 Jun 2016 03:03:25 -0400 Received: from e23smtp05.au.ibm.com (e23smtp05.au.ibm.com [202.81.31.147]) by mx0a-001b2d01.pphosted.com with ESMTP id 23b3g1c1d4-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Fri, 03 Jun 2016 03:03:25 -0400 Received: from localhost by e23smtp05.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 3 Jun 2016 17:03:21 +1000 Received: from d23relay06.au.ibm.com (d23relay06.au.ibm.com [9.185.63.219]) by d23dlp03.au.ibm.com (Postfix) with ESMTP id 7BD9F3578067 for ; Fri, 3 Jun 2016 17:02:58 +1000 (EST) Received: from d23av01.au.ibm.com (d23av01.au.ibm.com [9.190.234.96]) by d23relay06.au.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id u5372mLU65994858 for ; Fri, 3 Jun 2016 17:02:53 +1000 Received: from d23av01.au.ibm.com (localhost [127.0.0.1]) by d23av01.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id u5372k0e017929 for ; Fri, 3 Jun 2016 17:02:47 +1000 Date: Fri, 03 Jun 2016 15:02:11 +0800 From: xinhui MIME-Version: 1.0 To: Benjamin Herrenschmidt , linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, virtualization@lists.linux-foundation.org CC: paulus@samba.org, mpe@ellerman.id.au, peterz@infradead.org, mingo@redhat.com, paulmck@linux.vnet.ibm.com, waiman.long@hpe.com Subject: Re: [PATCH v5 1/6] qspinlock: powerpc support qspinlock References: <1464859370-5162-1-git-send-email-xinhui.pan@linux.vnet.ibm.com> <1464859370-5162-3-git-send-email-xinhui.pan@linux.vnet.ibm.com> <1464917520.26773.11.camel@kernel.crashing.org> <1464917548.26773.12.camel@au1.ibm.com> <57510353.1020209@linux.vnet.ibm.com> <1464928427.26773.26.camel@kernel.crashing.org> In-Reply-To: <1464928427.26773.26.camel@kernel.crashing.org> Content-Type: text/plain; charset=utf-8; format=flowed Message-Id: <57512B73.5010005@linux.vnet.ibm.com> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 2016年06月03日 12:33, Benjamin Herrenschmidt wrote: > On Fri, 2016-06-03 at 12:10 +0800, xinhui wrote: >> On 2016年06月03日 09:32, Benjamin Herrenschmidt wrote: >>> On Fri, 2016-06-03 at 11:32 +1000, Benjamin Herrenschmidt wrote: >>>> On Thu, 2016-06-02 at 17:22 +0800, Pan Xinhui wrote: >>>>> >>>>> Base code to enable qspinlock on powerpc. this patch add some >>>>> #ifdef >>>>> here and there. Although there is no paravirt related code, we >> can >>>>> successfully build a qspinlock kernel after apply this patch. >>>> This is missing the IO_SYNC stuff ... It means we'll fail to do a >>>> full >>>> sync to order vs MMIOs. >>>> >>>> You need to add that back in the unlock path. >>> >>> Well, and in the lock path as well... >>> >> Oh, yes. I missed IO_SYNC stuff. >> >> thank you, Ben :) > > Ok couple of other things that would be nice from my perspective (and > Michael's) if you can produce them: > > - Some benchmarks of the qspinlock alone, without the PV stuff, > so we understand how much of the overhead is inherent to the > qspinlock and how much is introduced by the PV bits. > > - For the above, can you show (or describe) where the qspinlock > improves things compared to our current locks. While there's > theory and to some extent practice on x86, it would be nice to > validate the effects on POWER. > > - Comparative benchmark with the PV stuff in on a bare metal system > to understand the overhead there. > > - Comparative benchmark with the PV stuff under pHyp and KVM > Will do such benchmark tests in next days. thanks for your kind suggestions. :) > Spinlocks are fiddly and a critical piece of infrastructure, it's > important we fully understand the performance implications before we > decide to switch to a new model. > yes, We really need understand how {pv}qspinlock works in more complex cases. thanks xinhui > Cheers, > Ben. > From mboxrd@z Thu Jan 1 00:00:00 1970 From: xinhui Subject: Re: [PATCH v5 1/6] qspinlock: powerpc support qspinlock Date: Fri, 03 Jun 2016 15:02:11 +0800 Message-ID: <57512B73.5010005@linux.vnet.ibm.com> References: <1464859370-5162-1-git-send-email-xinhui.pan@linux.vnet.ibm.com> <1464859370-5162-3-git-send-email-xinhui.pan@linux.vnet.ibm.com> <1464917520.26773.11.camel@kernel.crashing.org> <1464917548.26773.12.camel@au1.ibm.com> <57510353.1020209@linux.vnet.ibm.com> <1464928427.26773.26.camel@kernel.crashing.org> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8"; Format="flowed" Content-Transfer-Encoding: base64 Return-path: In-Reply-To: <1464928427.26773.26.camel@kernel.crashing.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: Benjamin Herrenschmidt , linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, virtualization@lists.linux-foundation.org Cc: peterz@infradead.org, mpe@ellerman.id.au, waiman.long@hpe.com, mingo@redhat.com, paulus@samba.org, paulmck@linux.vnet.ibm.com List-Id: virtualization@lists.linuxfoundation.org CgpPbiAyMDE25bm0MDbmnIgwM+aXpSAxMjozMywgQmVuamFtaW4gSGVycmVuc2NobWlkdCB3cm90 ZToKPiBPbiBGcmksIDIwMTYtMDYtMDMgYXQgMTI6MTAgKzA4MDAsIHhpbmh1aSB3cm90ZToKPj4g T24gMjAxNuW5tDA25pyIMDPml6UgMDk6MzIsIEJlbmphbWluIEhlcnJlbnNjaG1pZHQgd3JvdGU6 Cj4+PiBPbiBGcmksIDIwMTYtMDYtMDMgYXQgMTE6MzIgKzEwMDAsIEJlbmphbWluIEhlcnJlbnNj aG1pZHQgd3JvdGU6Cj4+Pj4gT24gVGh1LCAyMDE2LTA2LTAyIGF0IDE3OjIyICswODAwLCBQYW4g WGluaHVpIHdyb3RlOgo+Pj4+Pgo+Pj4+PiBCYXNlIGNvZGUgdG8gZW5hYmxlIHFzcGlubG9jayBv biBwb3dlcnBjLiB0aGlzIHBhdGNoIGFkZCBzb21lCj4+Pj4+ICNpZmRlZgo+Pj4+PiBoZXJlIGFu ZCB0aGVyZS4gQWx0aG91Z2ggdGhlcmUgaXMgbm8gcGFyYXZpcnQgcmVsYXRlZCBjb2RlLCB3ZQo+ PiBjYW4KPj4+Pj4gc3VjY2Vzc2Z1bGx5IGJ1aWxkIGEgcXNwaW5sb2NrIGtlcm5lbCBhZnRlciBh cHBseSB0aGlzIHBhdGNoLgo+Pj4+IFRoaXMgaXMgbWlzc2luZyB0aGUgSU9fU1lOQyBzdHVmZiAu Li4gSXQgbWVhbnMgd2UnbGwgZmFpbCB0byBkbyBhCj4+Pj4gZnVsbAo+Pj4+IHN5bmMgdG8gb3Jk ZXIgdnMgTU1JT3MuCj4+Pj4KPj4+PiBZb3UgbmVlZCB0byBhZGQgdGhhdCBiYWNrIGluIHRoZSB1 bmxvY2sgcGF0aC4KPj4+Cj4+PiBXZWxsLCBhbmQgaW4gdGhlIGxvY2sgcGF0aCBhcyB3ZWxsLi4u Cj4+Pgo+PiBPaCwgeWVzLiBJIG1pc3NlZCBJT19TWU5DIHN0dWZmLgo+Pgo+PiB0aGFuayB5b3Us IEJlbiA6KQo+Cj4gT2sgY291cGxlIG9mIG90aGVyIHRoaW5ncyB0aGF0IHdvdWxkIGJlIG5pY2Ug ZnJvbSBteSBwZXJzcGVjdGl2ZSAoYW5kCj4gTWljaGFlbCdzKSBpZiB5b3UgY2FuIHByb2R1Y2Ug dGhlbToKPgo+ICAgLSBTb21lIGJlbmNobWFya3Mgb2YgdGhlIHFzcGlubG9jayBhbG9uZSwgd2l0 aG91dCB0aGUgUFYgc3R1ZmYsCj4gICAgIHNvIHdlIHVuZGVyc3RhbmQgaG93IG11Y2ggb2YgdGhl IG92ZXJoZWFkIGlzIGluaGVyZW50IHRvIHRoZQo+ICAgICBxc3BpbmxvY2sgYW5kIGhvdyBtdWNo IGlzIGludHJvZHVjZWQgYnkgdGhlIFBWIGJpdHMuCj4KPiAgIC0gRm9yIHRoZSBhYm92ZSwgY2Fu IHlvdSBzaG93IChvciBkZXNjcmliZSkgd2hlcmUgdGhlIHFzcGlubG9jawo+ICAgICBpbXByb3Zl cyB0aGluZ3MgY29tcGFyZWQgdG8gb3VyIGN1cnJlbnQgbG9ja3MuIFdoaWxlIHRoZXJlJ3MKPiAg ICAgdGhlb3J5IGFuZCB0byBzb21lIGV4dGVudCBwcmFjdGljZSBvbiB4ODYsIGl0IHdvdWxkIGJl IG5pY2UgdG8KPiAgICAgdmFsaWRhdGUgdGhlIGVmZmVjdHMgb24gUE9XRVIuCj4KPiAgIC0gQ29t cGFyYXRpdmUgYmVuY2htYXJrIHdpdGggdGhlIFBWIHN0dWZmIGluIG9uIGEgYmFyZSBtZXRhbCBz eXN0ZW0KPiAgICAgdG8gdW5kZXJzdGFuZCB0aGUgb3ZlcmhlYWQgdGhlcmUuCj4KPiAgIC0gQ29t cGFyYXRpdmUgYmVuY2htYXJrIHdpdGggdGhlIFBWIHN0dWZmIHVuZGVyIHBIeXAgYW5kIEtWTQo+ CldpbGwgZG8gc3VjaCBiZW5jaG1hcmsgdGVzdHMgaW4gbmV4dCBkYXlzLgp0aGFua3MgZm9yIHlv dXIga2luZCBzdWdnZXN0aW9ucy4gOikKCj4gU3BpbmxvY2tzIGFyZSBmaWRkbHkgYW5kIGEgY3Jp dGljYWwgcGllY2Ugb2YgaW5mcmFzdHJ1Y3R1cmUsIGl0J3MKPiBpbXBvcnRhbnQgd2UgZnVsbHkg dW5kZXJzdGFuZCB0aGUgcGVyZm9ybWFuY2UgaW1wbGljYXRpb25zIGJlZm9yZSB3ZQo+IGRlY2lk ZSB0byBzd2l0Y2ggdG8gYSBuZXcgbW9kZWwuCj4KeWVzLCBXZSByZWFsbHkgbmVlZCB1bmRlcnN0 YW5kIGhvdyB7cHZ9cXNwaW5sb2NrIHdvcmtzIGluIG1vcmUgY29tcGxleCBjYXNlcy4KCnRoYW5r cwp4aW5odWkKPiBDaGVlcnMsCj4gQmVuLgo+CgpfX19fX19fX19fX19fX19fX19fX19fX19fX19f X19fX19fX19fX19fX19fX19fXwpWaXJ0dWFsaXphdGlvbiBtYWlsaW5nIGxpc3QKVmlydHVhbGl6 YXRpb25AbGlzdHMubGludXgtZm91bmRhdGlvbi5vcmcKaHR0cHM6Ly9saXN0cy5saW51eGZvdW5k YXRpb24ub3JnL21haWxtYW4vbGlzdGluZm8vdmlydHVhbGl6YXRpb24=