diff for duplicates of <1491089381.9734.2.camel@sandisk.com> diff --git a/a/1.txt b/N1/1.txt index f52a622..b582d75 100644 --- a/a/1.txt +++ b/N1/1.txt @@ -1,29 +1,34 @@ -T24gU2F0LCAyMDE3LTA0LTAxIGF0IDE2OjA3IC0wNjAwLCBKZW5zIEF4Ym9lIHdyb3RlOg0KPiBP -biAwNC8wMS8yMDE3IDAxOjU1IFBNLCBPbWFyIFNhbmRvdmFsIHdyb3RlOg0KPiA+IEZyb206IE9t -YXIgU2FuZG92YWwgPG9zYW5kb3ZAZmIuY29tPg0KPiA+IA0KPiA+IFRoaXMgcGF0Y2ggaW50cm9k -dWNlcyBhIG5ldyBJL08gc2NoZWR1bGVyIGJhc2VkIG9uIHRoZSBjbGFzc2ljIHJhbmRvbQ0KPiA+ -IGVhcmx5IGRldGVjdGlvbiBhY3RpdmUgcXVldWUgbWFuYWdlbWVudCBhbGdvcml0aG0gWzFdLiBS -YW5kb20gZWFybHkNCj4gPiBkZXRlY3Rpb24gaXMgb25lIG9mIHRoZSBzaW1wbGVzdCBhbmQgbW9z -dCBzdHVkaWVkIEFRTSBhbGdvcml0aG1zIGZvcg0KPiA+IG5ldHdvcmtpbmcsIGJ1dCB1bnRpbCBu -b3csIGl0IGhhc24ndCBiZWVuIGFwcGxpZWQgdG8gZGlzayBJL08NCj4gPiBzY2hlZHVsaW5nLg0K -PiA+IA0KPiA+IFdoZW4gYXBwbGllZCB0byBuZXR3b3JrIHJvdXRlcnMsIFJFRCBwcm9iYWJpbGlz -dGljYWxseSBlaXRoZXIgbWFya3MNCj4gPiBwYWNrZXRzIHdpdGggRUNOIG9yIGRyb3BzIHRoZW0s -IGRlcGVuZGluZyBvbiB0aGUgY29uZmlndXJhdGlvbi4gV2hlbg0KPiA+IGRlYWxpbmcgd2l0aCBk -aXNrIEkvTywgUE9TSVggZG9lcyBub3QgaGF2ZSBhbnkgbWVjaGFuaXNtIHdpdGggd2hpY2ggdG8N -Cj4gPiBub3RpZnkgdGhlIGNhbGxlciB0aGF0IHRoZSBkaXNrIGlzIGNvbmdlc3RlZCwgc28gd2Ug -aW5zdGVhZCBvbmx5IHByb3ZpZGUNCj4gPiB0aGUgbGF0dGVyIHN0cmF0ZWd5LiBJbmNsdWRlZCBp -biB0aGlzIHBhdGNoIGlzIGEgbWlub3IgY2hhbmdlIHRvIHRoZQ0KPiA+IGJsay1tcSB0byBzdXBw -b3J0IHRoaXMuDQo+IA0KPiBUaGlzIGlzIGdyZWF0IHdvcmsuIElmIHdlIGNvbWJpbmUgdGhpcyB3 -aXRoIGEgdGhpbiBwcm92aXNpb25pbmcgdGFyZ2V0LA0KPiB3ZSBjYW4gZXZlbiB1c2UgdGhpcyB0 -byBzYXZlIHNwYWNlIG9uIHRoZSBiYWNrZW5kLiBCZXR0ZXIgbGF0ZW5jaWVzLA0KPiBBTkQgbG93 -ZXIgZGlzayB1dGlsaXphdGlvbi4NCj4gDQo+IEknbSB0ZW1wdGVkIHRvIGp1c3QgcXVldWUgdGhp -cyB1cCBmb3IgdGhpcyBjeWNsZSBhbmQgbWFrZSBpdCB0aGUgZGVmYXVsdC4NCg0KSGVsbG8gSmVu -cywNCg0KRGlkIHlvdSBtZWFuIG1ha2luZyB0aGlzIHRoZSBkZWZhdWx0IHNjaGVkdWxlciBmb3Ig -U1NEcyBvbmx5IG9yIGZvciBhbGwgdHlwZXMNCm9mIGJsb2NrIGRldmljZXM/IE91ciAoV2VzdGVy -biBEaWdpdGFsKSBleHBlcmllbmNlIGlzIHRoYXQgYW55IEkvTyBzY2hlZHVsZXINCnRoYXQgbGlt -aXRzIHRoZSBxdWV1ZSBkZXB0aCByZWR1Y2VzIHRocm91Z2hwdXQgZm9yIGF0IGxlYXN0IGRhdGEt -Y2VudGVyIHN0eWxlDQp3b3JrbG9hZHMgd2hlbiB1c2luZyBoYXJkIGRpc2tzLiBUaGlzIGlzIHdo -eSBBZGFtIGlzIHdvcmtpbmcgb24gaW1wcm92aW5nIEkvTw0KcHJpb3JpdHkgc3VwcG9ydCBmb3Ig -dGhlIExpbnV4IGJsb2NrIGxheWVyLiBUaGF0IGFwcHJvYWNoIG5hbWVseSBhbGxvd3MgdG8NCnJl -ZHVjZSBsYXRlbmN5IG9mIGNlcnRhaW4gcmVxdWVzdHMgd2l0aG91dCBzaWduaWZpY2FudGx5IGlt -cGFjdGluZyBhdmVyYWdlDQpsYXRlbmN5IGFuZCB0aHJvdWdocHV0Lg0KDQpCYXJ0Lg== +On Sat, 2017-04-01 at 16:07 -0600, Jens Axboe wrote: +> On 04/01/2017 01:55 PM, Omar Sandoval wrote: +> > From: Omar Sandoval <osandov@fb.com> +> > +> > This patch introduces a new I/O scheduler based on the classic random +> > early detection active queue management algorithm [1]. Random early +> > detection is one of the simplest and most studied AQM algorithms for +> > networking, but until now, it hasn't been applied to disk I/O +> > scheduling. +> > +> > When applied to network routers, RED probabilistically either marks +> > packets with ECN or drops them, depending on the configuration. When +> > dealing with disk I/O, POSIX does not have any mechanism with which to +> > notify the caller that the disk is congested, so we instead only provide +> > the latter strategy. Included in this patch is a minor change to the +> > blk-mq to support this. +> +> This is great work. If we combine this with a thin provisioning target, +> we can even use this to save space on the backend. Better latencies, +> AND lower disk utilization. +> +> I'm tempted to just queue this up for this cycle and make it the default. + +Hello Jens, + +Did you mean making this the default scheduler for SSDs only or for all types +of block devices? Our (Western Digital) experience is that any I/O scheduler +that limits the queue depth reduces throughput for at least data-center style +workloads when using hard disks. This is why Adam is working on improving I/O +priority support for the Linux block layer. That approach namely allows to +reduce latency of certain requests without significantly impacting average +latency and throughput. + +Bart. diff --git a/a/content_digest b/N1/content_digest index 200bdd8..e1da4b3 100644 --- a/a/content_digest +++ b/N1/content_digest @@ -10,34 +10,39 @@ "Cc\0kernel-team@fb.com <kernel-team@fb.com>\0" "\00:1\0" "b\0" - "T24gU2F0LCAyMDE3LTA0LTAxIGF0IDE2OjA3IC0wNjAwLCBKZW5zIEF4Ym9lIHdyb3RlOg0KPiBP\n" - "biAwNC8wMS8yMDE3IDAxOjU1IFBNLCBPbWFyIFNhbmRvdmFsIHdyb3RlOg0KPiA+IEZyb206IE9t\n" - "YXIgU2FuZG92YWwgPG9zYW5kb3ZAZmIuY29tPg0KPiA+IA0KPiA+IFRoaXMgcGF0Y2ggaW50cm9k\n" - "dWNlcyBhIG5ldyBJL08gc2NoZWR1bGVyIGJhc2VkIG9uIHRoZSBjbGFzc2ljIHJhbmRvbQ0KPiA+\n" - "IGVhcmx5IGRldGVjdGlvbiBhY3RpdmUgcXVldWUgbWFuYWdlbWVudCBhbGdvcml0aG0gWzFdLiBS\n" - "YW5kb20gZWFybHkNCj4gPiBkZXRlY3Rpb24gaXMgb25lIG9mIHRoZSBzaW1wbGVzdCBhbmQgbW9z\n" - "dCBzdHVkaWVkIEFRTSBhbGdvcml0aG1zIGZvcg0KPiA+IG5ldHdvcmtpbmcsIGJ1dCB1bnRpbCBu\n" - "b3csIGl0IGhhc24ndCBiZWVuIGFwcGxpZWQgdG8gZGlzayBJL08NCj4gPiBzY2hlZHVsaW5nLg0K\n" - "PiA+IA0KPiA+IFdoZW4gYXBwbGllZCB0byBuZXR3b3JrIHJvdXRlcnMsIFJFRCBwcm9iYWJpbGlz\n" - "dGljYWxseSBlaXRoZXIgbWFya3MNCj4gPiBwYWNrZXRzIHdpdGggRUNOIG9yIGRyb3BzIHRoZW0s\n" - "IGRlcGVuZGluZyBvbiB0aGUgY29uZmlndXJhdGlvbi4gV2hlbg0KPiA+IGRlYWxpbmcgd2l0aCBk\n" - "aXNrIEkvTywgUE9TSVggZG9lcyBub3QgaGF2ZSBhbnkgbWVjaGFuaXNtIHdpdGggd2hpY2ggdG8N\n" - "Cj4gPiBub3RpZnkgdGhlIGNhbGxlciB0aGF0IHRoZSBkaXNrIGlzIGNvbmdlc3RlZCwgc28gd2Ug\n" - "aW5zdGVhZCBvbmx5IHByb3ZpZGUNCj4gPiB0aGUgbGF0dGVyIHN0cmF0ZWd5LiBJbmNsdWRlZCBp\n" - "biB0aGlzIHBhdGNoIGlzIGEgbWlub3IgY2hhbmdlIHRvIHRoZQ0KPiA+IGJsay1tcSB0byBzdXBw\n" - "b3J0IHRoaXMuDQo+IA0KPiBUaGlzIGlzIGdyZWF0IHdvcmsuIElmIHdlIGNvbWJpbmUgdGhpcyB3\n" - "aXRoIGEgdGhpbiBwcm92aXNpb25pbmcgdGFyZ2V0LA0KPiB3ZSBjYW4gZXZlbiB1c2UgdGhpcyB0\n" - "byBzYXZlIHNwYWNlIG9uIHRoZSBiYWNrZW5kLiBCZXR0ZXIgbGF0ZW5jaWVzLA0KPiBBTkQgbG93\n" - "ZXIgZGlzayB1dGlsaXphdGlvbi4NCj4gDQo+IEknbSB0ZW1wdGVkIHRvIGp1c3QgcXVldWUgdGhp\n" - "cyB1cCBmb3IgdGhpcyBjeWNsZSBhbmQgbWFrZSBpdCB0aGUgZGVmYXVsdC4NCg0KSGVsbG8gSmVu\n" - "cywNCg0KRGlkIHlvdSBtZWFuIG1ha2luZyB0aGlzIHRoZSBkZWZhdWx0IHNjaGVkdWxlciBmb3Ig\n" - "U1NEcyBvbmx5IG9yIGZvciBhbGwgdHlwZXMNCm9mIGJsb2NrIGRldmljZXM/IE91ciAoV2VzdGVy\n" - "biBEaWdpdGFsKSBleHBlcmllbmNlIGlzIHRoYXQgYW55IEkvTyBzY2hlZHVsZXINCnRoYXQgbGlt\n" - "aXRzIHRoZSBxdWV1ZSBkZXB0aCByZWR1Y2VzIHRocm91Z2hwdXQgZm9yIGF0IGxlYXN0IGRhdGEt\n" - "Y2VudGVyIHN0eWxlDQp3b3JrbG9hZHMgd2hlbiB1c2luZyBoYXJkIGRpc2tzLiBUaGlzIGlzIHdo\n" - "eSBBZGFtIGlzIHdvcmtpbmcgb24gaW1wcm92aW5nIEkvTw0KcHJpb3JpdHkgc3VwcG9ydCBmb3Ig\n" - "dGhlIExpbnV4IGJsb2NrIGxheWVyLiBUaGF0IGFwcHJvYWNoIG5hbWVseSBhbGxvd3MgdG8NCnJl\n" - "ZHVjZSBsYXRlbmN5IG9mIGNlcnRhaW4gcmVxdWVzdHMgd2l0aG91dCBzaWduaWZpY2FudGx5IGlt\n" - cGFjdGluZyBhdmVyYWdlDQpsYXRlbmN5IGFuZCB0aHJvdWdocHV0Lg0KDQpCYXJ0Lg== + "On Sat, 2017-04-01 at 16:07 -0600, Jens Axboe wrote:\n" + "> On 04/01/2017 01:55 PM, Omar Sandoval wrote:\n" + "> > From: Omar Sandoval <osandov@fb.com>\n" + "> > \n" + "> > This patch introduces a new I/O scheduler based on the classic random\n" + "> > early detection active queue management algorithm [1]. Random early\n" + "> > detection is one of the simplest and most studied AQM algorithms for\n" + "> > networking, but until now, it hasn't been applied to disk I/O\n" + "> > scheduling.\n" + "> > \n" + "> > When applied to network routers, RED probabilistically either marks\n" + "> > packets with ECN or drops them, depending on the configuration. When\n" + "> > dealing with disk I/O, POSIX does not have any mechanism with which to\n" + "> > notify the caller that the disk is congested, so we instead only provide\n" + "> > the latter strategy. Included in this patch is a minor change to the\n" + "> > blk-mq to support this.\n" + "> \n" + "> This is great work. If we combine this with a thin provisioning target,\n" + "> we can even use this to save space on the backend. Better latencies,\n" + "> AND lower disk utilization.\n" + "> \n" + "> I'm tempted to just queue this up for this cycle and make it the default.\n" + "\n" + "Hello Jens,\n" + "\n" + "Did you mean making this the default scheduler for SSDs only or for all types\n" + "of block devices? Our (Western Digital) experience is that any I/O scheduler\n" + "that limits the queue depth reduces throughput for at least data-center style\n" + "workloads when using hard disks. This is why Adam is working on improving I/O\n" + "priority support for the Linux block layer. That approach namely allows to\n" + "reduce latency of certain requests without significantly impacting average\n" + "latency and throughput.\n" + "\n" + Bart. -883dc446049746c509209611a56de02a25b7fb14a0a3852a601544ebdb8cad32 +44f693d413f474778112de04bc8d191b46d34057ff1c949b6e6b20e4c6cc41b2
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