From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Jan Beulich" Subject: Re: further post-Meltdown-bad-aid performance thoughts Date: Mon, 22 Jan 2018 06:30:19 -0700 Message-ID: <5A65F57B02000078001A11B7@prv-mh.provo.novell.com> References: <5A6210B502000078001A06A5@prv-mh.provo.novell.com> <6134e80b-8fd0-8a7d-61c8-df5892685c63@citrix.com> <5A622C9602000078001A0847@prv-mh.provo.novell.com> <5A65BC0102000078001A0ED5@prv-mh.provo.novell.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Return-path: Received: from us1-rack-dfw2.inumbo.com ([104.130.134.6]) by lists.xenproject.org with esmtp (Exim 4.84_2) (envelope-from ) id 1edcB7-00070l-JQ for xen-devel@lists.xenproject.org; Mon, 22 Jan 2018 13:30:25 +0000 In-Reply-To: Content-Disposition: inline List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" To: George Dunlap Cc: George Dunlap , Andrew Cooper , xen-devel List-Id: xen-devel@lists.xenproject.org Pj4+IE9uIDIyLjAxLjE4IGF0IDEzOjMzLCA8Z2VvcmdlLmR1bmxhcEBjaXRyaXguY29tPiB3cm90 ZToKPiBPbiAwMS8yMi8yMDE4IDA5OjI1IEFNLCBKYW4gQmV1bGljaCB3cm90ZToKPj4+Pj4gT24g MTkuMDEuMTggYXQgMTg6MDAsIDxnZW9yZ2UuZHVubGFwQGNpdHJpeC5jb20+IHdyb3RlOgo+Pj4g T24gMDEvMTkvMjAxOCAwNDozNiBQTSwgSmFuIEJldWxpY2ggd3JvdGU6Cj4+Pj4+Pj4gT24gMTku MDEuMTggYXQgMTY6NDMsIDxnZW9yZ2UuZHVubGFwQGNpdHJpeC5jb20+IHdyb3RlOgo+Pj4+PiBT byB3aGF0IGlmIGluc3RlYWQgb2YgdHJ5aW5nIHRvIGNsb3NlIHRoZSAid2luZG93cyIsIHdlIG1h ZGUgaXQgc28gdGhhdAo+Pj4+PiB0aGVyZSB3YXMgbm90aGluZyB0aHJvdWdoIHRoZSB3aW5kb3dz IHRvIHNlZT8gIElmIG5vIG1hdHRlciB3aGF0IHRoZQo+Pj4+PiBoeXBlcnZpc29yIHNwZWN1bGF0 aXZlbHkgZXhlY3V0ZWQsIG5vdGhpbmcgc2Vuc2l0aXZlIHdhcyB2aXNpYmlsZSBleGNlcHQKPj4+ Pj4gd2hhdCBhIHZjcHUgd2FzIGFscmVhZHkgYWxsb3dlZCB0byBzZWUsCj4+Pj4KPj4+PiBJIHRo aW5rIHlvdSBkaWRuJ3QgZmluaXNoIHlvdXIgc2VudGVuY2UgaGVyZSwgYnV0IEkgYWxzbyB0aGlu ayBJCj4+Pj4gY2FuIGd1ZXNzIHRoZSBtaXNzaW5nIHBhcnQuIFRoZXJlJ3MgYSBwcmljZSB0byBw YXkgZm9yIHN1Y2ggYW4KPj4+PiBhcHByb2FjaCB0aG91Z2ggLSBpdGVyYXRpbmcgb3ZlciBkb21h aW5zLCBvciB2Q1BVLXMgb2YgYQo+Pj4+IGRvbWFpbiAoanVzdCBhcyBhbiBleGFtcGxlKSB3b3Vs ZG4ndCBiZSBzaW1wbGUgbGlzdCB3YWxrcwo+Pj4+IGFueW1vcmUuIFRoZXJlIGFyZSBjZXJ0YWlu bHkgb3RoZXIgdGhpbmdzLiBJT1cgLSB5ZXMsIGFuZAo+Pj4+IGFwcHJvYWNoIGxpa2UgdGhpcyBz ZWVtcyBwb3NzaWJsZSwgYnV0IHdpdGggYWxsIHRoZSBsb3N0Cj4+Pj4gcGVyZm9ybWFuY2UgSSB0 aGluayB3ZSBzaG91bGRuJ3QgZ28gb3ZlcmJvYXJkIHdpdGggZnVydGhlcgo+Pj4+IGhpZGluZy4K Pj4+Cj4+PiBSaWdodCwgc28gdGhlIG5leHQgcXVlc3Rpb246IHdoYXQgaW5mb3JtYXRpb24gKmZy b20gb3RoZXIgZ3Vlc3RzKiBhcmUKPj4+IHNlbnNpdGl2ZT8KPj4+Cj4+PiBPYnZpb3VzbHkgdGhl IGd1ZXN0IHJlZ2lzdGVycyBhcmUgc2Vuc2l0aXZlLiAgQnV0IGhvdyBtdWNoIG9mIHRoZQo+Pj4g aW5mb3JtYXRpb24gaW4gdmNwdSBzdHJ1Y3QgdGhhdCB3ZSBhY3R1YWxseSBuZWVkIHRvIGhhdmUg InRvIGhhbmQiIGlzCj4+PiBhY3R1YWxseSBzZW5zaXRpdmUgaW5mb3JtYXRpb24gdGhhdCB3ZSBu ZWVkIHRvIGhpZGUgZnJvbSBvdGhlciBWTXM/Cj4+IAo+PiBOb25lLCBJIHRoaW5rLiBCdXQgdGhh dCdzIG5vdCB0aGUgbWFpbiBhc3BlY3QgaGVyZS4gc3RydWN0IHZjcHUKPj4gaW5zdGFuY2VzIGNv bWUgYW5kIGdvLCB3aGljaCB3b3VsZCBtZWFuIHdlJ2QgaGF2ZSB0bwo+PiBwZXJtYW5lbnRseSB1 cGRhdGUgd2hhdCBpcyBvciBpcyBub3QgYmVpbmcgZXhwb3NlZCBpbiB0aGUgcGFnZQo+PiB0YWJs ZXMgdXNlZC4gVGhpcywgd2hpbGUgc29sdmFibGUsIGlzIGdvaW5nIHRvIGJlIGEgc2lnbmlmaWNh bnQKPj4gYnVyZGVuIGluIHRlcm1zIG9mIHN5bmNocm9uaXppbmcgcGFnZSB0YWJsZXMgKGlmIHdl IGNvbnRpbnVlIHRvCj4+IHVzZSBwZXItQ1BVIG9uZXMpIGFuZC9vciBUTEIgc2hvb3Rkb3duLiBX aGVyZWFzIGlmIG9ubHkgdGhlCj4+IHJ1bm5pbmcgdkNQVSdzIHN0cnVjdHVyZSAoYW5kIGl0J3Mg c3RydWN0IGRvbWFpbikgYXJlIGV4cG9zZWQsCj4+IG5vIHN1Y2ggc3luY2hyb25pemF0aW9uIGlz IG5lZWRlZCAodGhpbmdzIHdvdWxkIHNpbXBseSBiZQo+PiB1cGRhdGVkIGR1cmluZyBjb250ZXh0 IHN3aXRjaCkuCj4gCj4gSSdtIG5vdCBzdXJlIHdlJ3JlIGFjdHVhbGx5IGNvbW11bmljYXRpbmcu Cj4gCj4gQ29ycmVjdCBtZSBpZiBJJ20gd3Jvbmc7IGF0IHRoZSBtb21lbnQsIHVuZGVyIFhQVEks IGh5cGVyY2FsbHMgcnVubmluZwo+IHVuZGVyIFhlbiBzdGlsbCBoYXZlIGFjY2VzcyB0byBhbGwg b2YgaG9zdCBtZW1vcnkuICBUbyBwcm90ZWN0IGFnYWluc3QKPiBTUDMsIHdlIHJlbW92ZSBhbG1v c3QgYWxsIFhlbiBtZW1vcnkgZnJvbSB0aGUgYWRkcmVzcyBzcGFjZSBiZWZvcmUKPiBzd2l0Y2hp bmcgdG8gdGhlIGd1ZXN0Lgo+IAo+IFdoYXQgSSdtIHByb3Bvc2luZyBpcyBzb21ldGhpbmcgbGlr ZSB0aGlzOgo+IAo+ICogV2UgaGF2ZSBhICJnbG9iYWwiIHJlZ2lvbiBvZiBYZW4gbWVtb3J5IHRo YXQgaXMgbWFwcGVkIGJ5IGFsbAo+IHByb2Nlc3NvcnMuICBUaGlzIHdpbGwgY29udGFpbiBldmVy eXRoaW5nIHdlIGNvbnNpZGVyIG5vdCBzZW5zaXRpdmU7Cj4gaW5jbHVkaW5nIFhlbiB0ZXh0IHNl Z21lbnRzLCBhbmQgbW9zdCBkb21haW4gYW5kIHZjcHUgZGF0YS4gIEJ1dCBpdCB3aWxsCj4gKm5v dCogbWFwIGFsbCBvZiBob3N0IG1lbW9yeSwgbm9yIGhhdmUgYWNjZXNzIHRvIHNlbnNpdGl2ZSBk YXRhLCBzdWNoIGFzCj4gdmNwdSByZWdpc3RlciBzdGF0ZS4KPiAKPiAqIFdlIGhhdmUgcGVyLWNw dSAibG9jYWwiIHJlZ2lvbnMuICBJbiB0aGlzIHJlZ2lvbiB3ZSB3aWxsIG1hcCwKPiBvbi1kZW1h bmQsIGd1ZXN0IG1lbW9yeSB3aGljaCBpcyBuZWVkZWQgdG8gcGVyZm9ybSBjdXJyZW50IG9wZXJh dGlvbnMuCj4gKFdlIGNhbiBjb25zaWRlciBob3cgc3RyaWN0bHkgd2UgbmVlZCB0byB1bm1hcCBt ZW1vcnkgYWZ0ZXIgdXNpbmcgaXQuKQo+IFdlIHdpbGwgYWxzbyBtYXAgdGhlIGN1cnJlbnQgdmNw dSdzIHJlZ2lzdGVycy4KPiAKPiAqIE9uIGVudHJ5IHRvIGEgNjQtYml0IFBWIGd1ZXN0LCB3ZSBk b24ndCBjaGFuZ2UgdGhlIG1hcHBpbmcgYXQgYWxsLgo+IAo+IE5vdywgbm8gbWF0dGVyIHdoYXQg dGhlIHNwZWN1bGF0aXZlIGF0dGFjayAtLSBTUDEsIFNQMiwgb3IgU1AzIC0tIGEgdmNwdQo+IGNh biBvbmx5IGFjY2VzcyBpdHMgb3duIFJBTSBhbmQgcmVnaXN0ZXJzLiAgVGhlcmUncyBubyBleHRy YSBvdmVyaGVhZCB0bwo+IGNvbnRleHQgc3dpdGNoaW5nIGludG8gb3Igb3V0IG9mIHRoZSBoeXBl cnZpc29yLgoKQW5kIHdlIHdvdWxkIG9wZW4gYmFjayB1cCB0aGUgU1AzIHZhcmlhbnQgb2YgZ3Vl c3QgdXNlciBtb2RlCmF0dGFja2luZyBpdHMgb3duIGtlcm5lbCBieSBnb2luZyB0aHJvdWdoIHRo ZSBYZW4gbWFwcGluZ3MuIEkKY2FuJ3QgZXhjbHVkZSB0aGF0IHZhcmlhbnRzIG9mIFNQMSAobGVz cyBsaWtlbHkgU1AyKSBhbGxvd2luZyBpbmRpcmVjdApndWVzdC11c2VyIC0+IGd1ZXN0LWtlcm5l bCBhdHRhY2tzIGNvdWxkbid0IGJlIGZvdW5kLgoKPiBHaXZlbiB0aGF0LCBJIGRvbid0IHVuZGVy c3RhbmQgd2hhdCB0aGUgZm9sbG93aW5nIGNvbW1lbnRzIG1lYW46Cj4gCj4gIlRoZXJlJ3MgYSBw cmljZSB0byBwYXkgZm9yIHN1Y2ggYW4gYXBwcm9hY2ggdGhvdWdoIC0gaXRlcmF0aW5nIG92ZXIK PiBkb21haW5zLCBvciB2Q1BVLXMgb2YgYSBkb21haW4gKGp1c3QgYXMgYW4gZXhhbXBsZSkgd291 bGRuJ3QgYmUgc2ltcGxlCj4gbGlzdCB3YWxrcyBhbnltb3JlLiIKPiAKPiBJZiB3ZSByZW1vdmUg c2Vuc2l0aXZlIGluZm9ybWF0aW9uIGZyb20gdGhlIGRvbWFpbiBhbmQgdmNwdSBzdHJ1Y3RzLAo+ IHRoZW4gYW55IGJpdCBvZiBoeXBlcnZpc29yIGNvZGUgY2FuIGl0ZXJhdGUgb3ZlciBkb21haW4g YW5kIHZjcHUgc3RydWN0cwo+IGF0IHdpbGw7IG9ubHkgaWYgdGhleSBhY3R1YWxseSBuZWVkIHRv IHJlYWQgb3Igd3JpdGUgc2Vuc2l0aXZlIGRhdGEgd2lsbAo+IHRoZXkgaGF2ZSB0byBwZXJmb3Jt IGFuIGV4cGVuc2l2ZSBtYXAvdW5tYXAgb3BlcmF0aW9uLiAgQnV0IGluIGdlbmVyYWwsCj4gdG8g cmVhZCBhbm90aGVyIHZjcHUncyByZWdpc3RlcnMgeW91IGFscmVhZHkgbmVlZCB0byBkbyBhIHZj cHVfcGF1c2UoKSAvCj4gdmNwdV91bnBhdXNlKCksIHdoaWNoIGludm9sdmVzIGF0IGxlYXN0IHR3 byBJUElzICh3aXRoIG9uZQo+IHNwaW4tYW5kLXdhaXQpLCBzbyBpdCBkb2Vzbid0IHNlZW0gbGlr ZSB0aGF0IHNob3VsZCBhZGQgYSBsb3Qgb2YgZXh0cmEKPiBvdmVyaGVhZC4KClJlYWRpbmcgYW5v dGhlciB2Q1BVLXMgcmVnaXN0ZXIgY2FuJ3QgYmUgY29tcGFyZWQgd2l0aCBlLmcuCndhbnRpbmcg dG8gZGVsaXZlciBhbiBpbnRlcnJ1cHQgdG8gb3RoZXIgdGhhbiB0aGUgY3VycmVudGx5IHJ1bm5p bmcKdkNQVS4KCj4gInN0cnVjdCB2Y3B1IGluc3RhbmNlcyBjb21lIGFuZCBnbywgd2hpY2ggd291 bGQgbWVhbiB3ZSdkIGhhdmUgdG8KPiBwZXJtYW5lbnRseSB1cGRhdGUgd2hhdCBpcyBvciBpcyBu b3QgYmVpbmcgZXhwb3NlZCBpbiB0aGUgcGFnZSB0YWJsZXMKPiB1c2VkLiBUaGlzLCB3aGlsZSBz b2x2YWJsZSwgaXMgZ29pbmcgdG8gYmUgYSBzaWduaWZpY2FudCBidXJkZW4gaW4gdGVybXMKPiBv ZiBzeW5jaHJvbml6aW5nIHBhZ2UgdGFibGVzIChpZiB3ZSBjb250aW51ZSB0byB1c2UgcGVyLUNQ VSBvbmVzKSBhbmQvb3IKPiBUTEIgc2hvb3Rkb3duLiIKPiAKPiBJIGRvbid0IHVuZGVyc3RhbmQg d2hhdCB0aGlzIGlzIHJlZmVycmluZyB0byBpbiBteSBwcm9wb3NlZCBwbGFuIGFib3ZlLgoKSSBo YWQgc3BlY2lmaWNhbGx5IHNhaWQgdGhlc2Ugd2VyZSBqdXN0IGV4YW1wbGVzIChvbmVzIGNvbWlu ZyB0bwptaW5kIGltbWVkaWF0ZWx5KS4gT2YgY291cnNlIHNwbGl0dGluZyBzdWNoIHN0cnVjdHVy ZXMgaW4gdHdvIHBhcnRzCmlzIGFuIG9wdGlvbiwgYnV0IEknbSBub3Qgc3VyZSBpdCdzIGEgcmVh c29uYWJsZSBvbmUgKHdoaWNoIHBlcmhhcHMKZGVwZW5kcyBvbiBkZXRhaWxzIG9uIGhvdyB5b3Ug d291bGQgZW52aXNpb24gdGhlIGltcGxlbWVudGF0aW9uKS4KSWYgdGhlIHNwbGl0IG9mZiBwaWVj ZShzKSB3YXMvd2VyZSBiZWluZyByZWZlcnJlZCB0byBieSBwb2ludGVycyBvdXQKb2YgdGhlIG1h aW4gc3RydWN0dXJlLCB0aGVyZSB3b3VsZCBiZSBhIG1lYW5pbmdmdWwgcmlzayBvZiBzb21lCnBl cmhhcHMgcmFyZWx5IGV4ZWN1dGVkIHBpZWNlIG9mIGNvZGUgZGUtcmVmZXJlbmNpbmcgaXQgaW4g dGhlCndyb25nIGNvbnRleHQuIE90b2ggZW50aXJlbHkgaW5kZXBlbmRlbnQgc3RydWN0dXJlcyAo d2l0aG91dApwb2ludGVycyBpbiBlaXRoZXIgZGlyZWN0aW9uKSB3b3VsZCBuZWVkIGNhcmVmdWwg bWFuYWdlbWVudCBvZgp0aGVpciBsaWZlIHRpbWVzLCBzbyBvbmUgZG9lc24ndCBnbyBhd2F5IHdp dGhvdXQgdGhlIG90aGVyLgoKWW91IG1lbnRpb24gdGhlIHBvc3NpYmlsaXR5IG9mIG9uIGRlbWFu ZCBtYXBwaW5nIC0gaWYgZGF0YQpzdHJ1Y3R1cmVzIGFyZW4ndCB1c2VkIGZyZXF1ZW50bHksIHRo YXQncyBjZXJ0YWlubHkgYW4gb3B0aW9uLgpJbiB0aGUgZW5kIHRoZXJlJ3MgYSBsb3Qgb2YgdW5j ZXJ0YWludHkgaGVyZSB3aGV0aGVyIHRoZSBpbiB0aGVvcnkKbmljZSBvdXRsaW5lIGNvdWxkIGFj dHVhbGx5IGxpdmUgdXAgdG8gdGhlIHJlcXVpcmVtZW50cyBvZiBhbgphY3R1YWwgaW1wbGVtZW50 YXRpb24uIFlldCBjb25zaWRlcmluZyB0aGUgKHByZXN1bWFibHkpCmZ1bmRhbWVudGFsIHJlLXN0 cnVjdHVyaW5nIG9mIGRhdGEgd2hpY2ggd291bGQgYmUgcmVxdWlyZWQKaGVyZSBjYWxscyBmb3Ig YXQgbGVhc3Qgc29tZSBvZiB0aGlzIHVuY2VydGFpbnR5IHRvIGJlIGFkZHJlc3NlZApiZWZvcmUg YWN0dWFsbHkgbWFraW5nIGFuIGF0dGVtcHQgdG8gc3dpdGNoIG92ZXIgdG8gc3VjaCBhCm1vZGVs LgoKSmFuCgpfX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fXwpY ZW4tZGV2ZWwgbWFpbGluZyBsaXN0Clhlbi1kZXZlbEBsaXN0cy54ZW5wcm9qZWN0Lm9yZwpodHRw czovL2xpc3RzLnhlbnByb2plY3Qub3JnL21haWxtYW4vbGlzdGluZm8veGVuLWRldmVs