From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bart Van Assche Subject: Re: [PATCH 1/5] block: don't call blk_mq_delay_run_hw_queue() in case of BLK_STS_RESOURCE Date: Tue, 19 Sep 2017 15:36:35 +0000 Message-ID: <1505835394.2671.18.camel@wdc.com> References: <20170915164456.9803-1-ming.lei@redhat.com> <20170915164456.9803-2-ming.lei@redhat.com> <1505498249.3420.15.camel@wdc.com> <20170917124000.GB6289@ming.t460p> <1505747894.2685.6.camel@wdc.com> <20170919054308.GA2517@ming.t460p> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Return-path: In-Reply-To: <20170919054308.GA2517@ming.t460p> Content-Language: en-US Content-ID: <5462BC681FD65D4DB6D925A413648C94@namprd04.prod.outlook.com> Sender: linux-block-owner@vger.kernel.org To: "ming.lei@redhat.com" Cc: "linux-block@vger.kernel.org" , "hch@infradead.org" , "sagi@grimberg.me" , "snitzer@redhat.com" , "martin.petersen@oracle.com" , "linux-scsi@vger.kernel.org" , "axboe@fb.com" , "linux-nvme@lists.infradead.org" , "jejb@linux.vnet.ibm.com" , "loberman@redhat.com" , "dm-devel@redhat.com" List-Id: dm-devel.ids T24gVHVlLCAyMDE3LTA5LTE5IGF0IDEzOjQzICswODAwLCBNaW5nIExlaSB3cm90ZToNCj4gT24g TW9uLCBTZXAgMTgsIDIwMTcgYXQgMDM6MTg6MTZQTSArMDAwMCwgQmFydCBWYW4gQXNzY2hlIHdy b3RlOg0KPiA+IElmIHlvdSBhcmUgc3RpbGwgbG9va2luZyBhdCByZW1vdmluZyB0aGUgYmxrX21x X2RlbGF5X3J1bl9od19xdWV1ZSgpIGNhbGxzDQo+ID4gdGhlbiBJIHRoaW5rIHlvdSBhcmUgbG9v a2luZyBpbiB0aGUgd3JvbmcgZGlyZWN0aW9uLiBXaGF0IGtpbmQgb2YgcHJvYmxlbQ0KPiA+IGFy ZSB5b3UgdHJ5aW5nIHRvIHNvbHZlPyBJcyBpdCBwZXJoYXBzIHRoYXQgdGhlcmUgY2FuIGJlIGEg ZGVsYXkgYmV0d2Vlbg0KPiANCj4gQWN0dWFsbHkgdGhlIGltcHJvdmVtZW50IG9uIGRtLXJxIElP IHNjaGVkdWxlKHRoZSBwYXRjaCAyIH4gNSkgZG9lc24ndA0KPiBuZWVkIHRoaXMgcGF0Y2guDQoN ClRoZSBhcHByb2FjaCBvZiB0aGlzIHBhdGNoIHNlcmllcyBsb29rcyB3cm9uZyB0byBtZSBhbmQg cGF0Y2ggNS81IGlzIGFuIHVnbHkNCmhhY2sgaW4gbXkgb3Bpbmlvbi4gVGhhdCdzIHdoeSBJIGFz a2VkIHlvdSB0byBkcm9wIHRoZSBlbnRpcmUgcGF0Y2ggc2VyaWVzIGFuZA0KdG8gdGVzdCB3aGV0 aGVyIGluc2VydGluZyBhIHF1ZXVlIHJ1biBjYWxsIGludG8gdGhlIGRtLW1wYXRoIGVuZF9pbyBj YWxsYmFjaw0KeWllbGRzIGEgc2ltaWxhciBwZXJmb3JtYW5jZSBpbXByb3ZlbWVudCB0byB0aGUg cGF0Y2hlcyB5b3UgcG9zdGVkLiBQbGVhc2UgZG8NCm5vdCBleHBlY3QgbWUgdG8gc3BlbmQgbW9y ZSB0aW1lIG9uIHRoaXMgcGF0Y2ggc2VyaWVzIGlmIHlvdSBkbyBub3QgY29tZSB1cA0Kd2l0aCBt ZWFzdXJlbWVudCByZXN1bHRzIGZvciB0aGUgcHJvcG9zZWQgYWx0ZXJuYXRpdmUuDQoNCkJhcnQu From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Bart Van Assche To: "ming.lei@redhat.com" CC: "linux-block@vger.kernel.org" , "hch@infradead.org" , "sagi@grimberg.me" , "snitzer@redhat.com" , "martin.petersen@oracle.com" , "linux-scsi@vger.kernel.org" , "axboe@fb.com" , "linux-nvme@lists.infradead.org" , "jejb@linux.vnet.ibm.com" , "loberman@redhat.com" , "dm-devel@redhat.com" Subject: Re: [PATCH 1/5] block: don't call blk_mq_delay_run_hw_queue() in case of BLK_STS_RESOURCE Date: Tue, 19 Sep 2017 15:36:35 +0000 Message-ID: <1505835394.2671.18.camel@wdc.com> References: <20170915164456.9803-1-ming.lei@redhat.com> <20170915164456.9803-2-ming.lei@redhat.com> <1505498249.3420.15.camel@wdc.com> <20170917124000.GB6289@ming.t460p> <1505747894.2685.6.camel@wdc.com> <20170919054308.GA2517@ming.t460p> In-Reply-To: <20170919054308.GA2517@ming.t460p> Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Sender: linux-scsi-owner@vger.kernel.org List-ID: T24gVHVlLCAyMDE3LTA5LTE5IGF0IDEzOjQzICswODAwLCBNaW5nIExlaSB3cm90ZToNCj4gT24g TW9uLCBTZXAgMTgsIDIwMTcgYXQgMDM6MTg6MTZQTSArMDAwMCwgQmFydCBWYW4gQXNzY2hlIHdy b3RlOg0KPiA+IElmIHlvdSBhcmUgc3RpbGwgbG9va2luZyBhdCByZW1vdmluZyB0aGUgYmxrX21x X2RlbGF5X3J1bl9od19xdWV1ZSgpIGNhbGxzDQo+ID4gdGhlbiBJIHRoaW5rIHlvdSBhcmUgbG9v a2luZyBpbiB0aGUgd3JvbmcgZGlyZWN0aW9uLiBXaGF0IGtpbmQgb2YgcHJvYmxlbQ0KPiA+IGFy ZSB5b3UgdHJ5aW5nIHRvIHNvbHZlPyBJcyBpdCBwZXJoYXBzIHRoYXQgdGhlcmUgY2FuIGJlIGEg ZGVsYXkgYmV0d2Vlbg0KPiANCj4gQWN0dWFsbHkgdGhlIGltcHJvdmVtZW50IG9uIGRtLXJxIElP IHNjaGVkdWxlKHRoZSBwYXRjaCAyIH4gNSkgZG9lc24ndA0KPiBuZWVkIHRoaXMgcGF0Y2guDQoN ClRoZSBhcHByb2FjaCBvZiB0aGlzIHBhdGNoIHNlcmllcyBsb29rcyB3cm9uZyB0byBtZSBhbmQg cGF0Y2ggNS81IGlzIGFuIHVnbHkNCmhhY2sgaW4gbXkgb3Bpbmlvbi4gVGhhdCdzIHdoeSBJIGFz a2VkIHlvdSB0byBkcm9wIHRoZSBlbnRpcmUgcGF0Y2ggc2VyaWVzIGFuZA0KdG8gdGVzdCB3aGV0 aGVyIGluc2VydGluZyBhIHF1ZXVlIHJ1biBjYWxsIGludG8gdGhlIGRtLW1wYXRoIGVuZF9pbyBj YWxsYmFjaw0KeWllbGRzIGEgc2ltaWxhciBwZXJmb3JtYW5jZSBpbXByb3ZlbWVudCB0byB0aGUg cGF0Y2hlcyB5b3UgcG9zdGVkLiBQbGVhc2UgZG8NCm5vdCBleHBlY3QgbWUgdG8gc3BlbmQgbW9y ZSB0aW1lIG9uIHRoaXMgcGF0Y2ggc2VyaWVzIGlmIHlvdSBkbyBub3QgY29tZSB1cA0Kd2l0aCBt ZWFzdXJlbWVudCByZXN1bHRzIGZvciB0aGUgcHJvcG9zZWQgYWx0ZXJuYXRpdmUuDQoNCkJhcnQu From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bart.VanAssche@wdc.com (Bart Van Assche) Date: Tue, 19 Sep 2017 15:36:35 +0000 Subject: [PATCH 1/5] block: don't call blk_mq_delay_run_hw_queue() in case of BLK_STS_RESOURCE In-Reply-To: <20170919054308.GA2517@ming.t460p> References: <20170915164456.9803-1-ming.lei@redhat.com> <20170915164456.9803-2-ming.lei@redhat.com> <1505498249.3420.15.camel@wdc.com> <20170917124000.GB6289@ming.t460p> <1505747894.2685.6.camel@wdc.com> <20170919054308.GA2517@ming.t460p> Message-ID: <1505835394.2671.18.camel@wdc.com> On Tue, 2017-09-19@13:43 +0800, Ming Lei wrote: > On Mon, Sep 18, 2017@03:18:16PM +0000, Bart Van Assche wrote: > > If you are still looking at removing the blk_mq_delay_run_hw_queue() calls > > then I think you are looking in the wrong direction. What kind of problem > > are you trying to solve? Is it perhaps that there can be a delay between > > Actually the improvement on dm-rq IO schedule(the patch 2 ~ 5) doesn't > need this patch. The approach of this patch series looks wrong to me and patch 5/5 is an ugly hack in my opinion. That's why I asked you to drop the entire patch series and to test whether inserting a queue run call into the dm-mpath end_io callback yields a similar performance improvement to the patches you posted. Please do not expect me to spend more time on this patch series if you do not come up with measurement results for the proposed alternative. Bart.