diff for duplicates of <1507914527.13345.17.camel@wdc.com> diff --git a/a/1.txt b/N1/1.txt index 4307bce..ed6f30d 100644 --- a/a/1.txt +++ b/N1/1.txt @@ -1,28 +1,37 @@ -T24gU2F0LCAyMDE3LTEwLTE0IGF0IDAwOjQ1ICswODAwLCBNaW5nIExlaSB3cm90ZToNCj4gT24g -RnJpLCBPY3QgMTMsIDIwMTcgYXQgMDQ6MzE6MDRQTSArMDAwMCwgQmFydCBWYW4gQXNzY2hlIHdy -b3RlOg0KPiA+IE9uIFNhdCwgMjAxNy0xMC0xNCBhdCAwMDowNyArMDgwMCwgTWluZyBMZWkgd3Jv -dGU6DQo+ID4gPiBBY3R1YWxseSBpdCBpcyBpbiBob3QgcGF0aCwgZm9yIGV4YW1wbGUsIGxwZmMg -YW5kIHFsYTJ4eCdzIHF1ZXVlIGRlcHRoIGlzIDMsDQo+ID4gDQo+ID4gU29ycnkgYnV0IEkgZG91 -YnQgd2hldGhlciB0aGF0IGlzIGNvcnJlY3QuIE1vcmUgaW4gZ2VuZXJhbCwgSSBkb24ndCBrbm93 -IGFueSBtb2Rlcm4NCj4gPiBzdG9yYWdlIEhCQSBmb3Igd2hpY2ggdGhlIGRlZmF1bHQgcXVldWUg -ZGVwdGggaXMgc28gbG93Lg0KPiANCj4gWW91IGNhbiBncmVwOg0KPiANCj4gW21pbmdAbWluZyBs -aW51eF0kIGdpdCBncmVwIC1uIGNtZF9wZXJfbHVuIC4vZHJpdmVycy9zY3NpLyB8IGdyZXAgLUUg -InFsYTJ4eHh8bHBmYyINCg0KU3VjaCBhIGxvdyBxdWV1ZSBkZXB0aCB3aWxsIHJlc3VsdCBpbiBz -dWJvcHRpbWFsIHBlcmZvcm1hbmNlIGZvciBhZGFwdGVycw0KdGhhdCBjb21tdW5pY2F0ZSBvdmVy -IGEgc3RvcmFnZSBuZXR3b3JrLiBJIHRoaW5rIHRoYXQncyBhIGJ1ZyBhbmQgdGhhdCBib3RoDQph -ZGFwdGVycyBzdXBwb3J0IG11Y2ggaGlnaGVyIGNtZF9wZXJfbHVuIHZhbHVlcy4NCg0KKCtKYW1l -cyBTbWFydCkNCg0KSmFtZXMsIGNhbiB5b3UgZXhwbGFpbiB1cyB3aHkgY29tbWl0IDQ0NWNmNGY0 -ZDJhYSBkZWNyZWFzZWQgTFBGQ19DTURfUEVSX0xVTg0KZnJvbSAzMCB0byAzPyBXYXMgdGhhdCBw -ZXJoYXBzIGEgd29ya2Fyb3VuZCBmb3IgYSBidWcgaW4gYSBzcGVjaWZpYyB0YXJnZXQNCmltcGxl -bWVudGF0aW9uPw0KDQooK0hpbWFuc2h1IE1hZGhhbmkpDQoNCkhpbWFuc2h1LCBkbyB5b3UgcGVy -aGFwcyBrbm93IHdoZXRoZXIgaXQgaXMgc2FmZSB0byBpbmNyZWFzZSBjbWRfcGVyX2x1biBmb3IN -CnRoZSBxbGEyeHh4IGluaXRpYXRvciBkcml2ZXIgdG8gdGhlIHNjc2lfaG9zdC0+Y2FuX3F1ZXVl -IHZhbHVlPw0KDQo+IEV2ZW4gU1JQL0lCIGlzbid0IGJpZyB0b28sIGp1c3QgMzIuDQoNClRoZSBk -ZWZhdWx0IHZhbHVlIGZvciBpYl9zcnAgZm9yIGNtZF9wZXJfbHVuIGlzIDYyIGJ1dCB0aGF0IHZh -bHVlIGNhbiBiZQ0Kb3ZlcnJpZGRlbiBieSBzZWxlY3RpbmcgYW5vdGhlciB2YWx1ZSBpbiAvZXRj -L2RlZmF1bHQvc3JwX2RhZW1vbi5jb25mLiBOb3RlOg0KYSBsb3dlciB2YWx1ZSBpcyBzZWxlY3Rl -ZCBpZiBhZnRlciBTUlAgbG9naW4gaXQgYmVjb21lcyBjbGVhciB0aGF0IHRoZSB0YXJnZXQNCnF1 -ZXVlIGRlcHRoIGlzIGxvd2VyIHRoYW4gdGhlIGNtZF9wZXJfbHVuIHZhbHVlIHJlcXVlc3RlZCBi -eSB0aGUgdXNlci4gVGhpcw0KaXMgYSBwZXJmb3JtYW5jZSBvcHRpbWl6YXRpb24gYW5kIGF2b2lk -cyB0aGF0IHRoZSBTUlAgdGFyZ2V0IHN5c3RlbSBoYXMgdG8NCnNlbmQgYmFjayBCVVNZIHJlc3Bv -bnNlcyB0byB0aGUgaW5pdGlhdG9yLg0KDQpCYXJ0Lg== +On Sat, 2017-10-14 at 00:45 +0800, Ming Lei wrote: +> On Fri, Oct 13, 2017 at 04:31:04PM +0000, Bart Van Assche wrote: +> > On Sat, 2017-10-14 at 00:07 +0800, Ming Lei wrote: +> > > Actually it is in hot path, for example, lpfc and qla2xx's queue depth is 3, +> > +> > Sorry but I doubt whether that is correct. More in general, I don't know any modern +> > storage HBA for which the default queue depth is so low. +> +> You can grep: +> +> [ming@ming linux]$ git grep -n cmd_per_lun ./drivers/scsi/ | grep -E "qla2xxx|lpfc" + +Such a low queue depth will result in suboptimal performance for adapters +that communicate over a storage network. I think that's a bug and that both +adapters support much higher cmd_per_lun values. + +(+James Smart) + +James, can you explain us why commit 445cf4f4d2aa decreased LPFC_CMD_PER_LUN +from 30 to 3? Was that perhaps a workaround for a bug in a specific target +implementation? + +(+Himanshu Madhani) + +Himanshu, do you perhaps know whether it is safe to increase cmd_per_lun for +the qla2xxx initiator driver to the scsi_host->can_queue value? + +> Even SRP/IB isn't big too, just 32. + +The default value for ib_srp for cmd_per_lun is 62 but that value can be +overridden by selecting another value in /etc/default/srp_daemon.conf. Note: +a lower value is selected if after SRP login it becomes clear that the target +queue depth is lower than the cmd_per_lun value requested by the user. This +is a performance optimization and avoids that the SRP target system has to +send back BUSY responses to the initiator. + +Bart. diff --git a/a/content_digest b/N1/content_digest index 5192f82..680a860 100644 --- a/a/content_digest +++ b/N1/content_digest @@ -25,33 +25,42 @@ " james.smart@broadcom.com <james.smart@broadcom.com>\0" "\00:1\0" "b\0" - "T24gU2F0LCAyMDE3LTEwLTE0IGF0IDAwOjQ1ICswODAwLCBNaW5nIExlaSB3cm90ZToNCj4gT24g\n" - "RnJpLCBPY3QgMTMsIDIwMTcgYXQgMDQ6MzE6MDRQTSArMDAwMCwgQmFydCBWYW4gQXNzY2hlIHdy\n" - "b3RlOg0KPiA+IE9uIFNhdCwgMjAxNy0xMC0xNCBhdCAwMDowNyArMDgwMCwgTWluZyBMZWkgd3Jv\n" - "dGU6DQo+ID4gPiBBY3R1YWxseSBpdCBpcyBpbiBob3QgcGF0aCwgZm9yIGV4YW1wbGUsIGxwZmMg\n" - "YW5kIHFsYTJ4eCdzIHF1ZXVlIGRlcHRoIGlzIDMsDQo+ID4gDQo+ID4gU29ycnkgYnV0IEkgZG91\n" - "YnQgd2hldGhlciB0aGF0IGlzIGNvcnJlY3QuIE1vcmUgaW4gZ2VuZXJhbCwgSSBkb24ndCBrbm93\n" - "IGFueSBtb2Rlcm4NCj4gPiBzdG9yYWdlIEhCQSBmb3Igd2hpY2ggdGhlIGRlZmF1bHQgcXVldWUg\n" - "ZGVwdGggaXMgc28gbG93Lg0KPiANCj4gWW91IGNhbiBncmVwOg0KPiANCj4gW21pbmdAbWluZyBs\n" - "aW51eF0kIGdpdCBncmVwIC1uIGNtZF9wZXJfbHVuIC4vZHJpdmVycy9zY3NpLyB8IGdyZXAgLUUg\n" - "InFsYTJ4eHh8bHBmYyINCg0KU3VjaCBhIGxvdyBxdWV1ZSBkZXB0aCB3aWxsIHJlc3VsdCBpbiBz\n" - "dWJvcHRpbWFsIHBlcmZvcm1hbmNlIGZvciBhZGFwdGVycw0KdGhhdCBjb21tdW5pY2F0ZSBvdmVy\n" - "IGEgc3RvcmFnZSBuZXR3b3JrLiBJIHRoaW5rIHRoYXQncyBhIGJ1ZyBhbmQgdGhhdCBib3RoDQph\n" - "ZGFwdGVycyBzdXBwb3J0IG11Y2ggaGlnaGVyIGNtZF9wZXJfbHVuIHZhbHVlcy4NCg0KKCtKYW1l\n" - "cyBTbWFydCkNCg0KSmFtZXMsIGNhbiB5b3UgZXhwbGFpbiB1cyB3aHkgY29tbWl0IDQ0NWNmNGY0\n" - "ZDJhYSBkZWNyZWFzZWQgTFBGQ19DTURfUEVSX0xVTg0KZnJvbSAzMCB0byAzPyBXYXMgdGhhdCBw\n" - "ZXJoYXBzIGEgd29ya2Fyb3VuZCBmb3IgYSBidWcgaW4gYSBzcGVjaWZpYyB0YXJnZXQNCmltcGxl\n" - "bWVudGF0aW9uPw0KDQooK0hpbWFuc2h1IE1hZGhhbmkpDQoNCkhpbWFuc2h1LCBkbyB5b3UgcGVy\n" - "aGFwcyBrbm93IHdoZXRoZXIgaXQgaXMgc2FmZSB0byBpbmNyZWFzZSBjbWRfcGVyX2x1biBmb3IN\n" - "CnRoZSBxbGEyeHh4IGluaXRpYXRvciBkcml2ZXIgdG8gdGhlIHNjc2lfaG9zdC0+Y2FuX3F1ZXVl\n" - "IHZhbHVlPw0KDQo+IEV2ZW4gU1JQL0lCIGlzbid0IGJpZyB0b28sIGp1c3QgMzIuDQoNClRoZSBk\n" - "ZWZhdWx0IHZhbHVlIGZvciBpYl9zcnAgZm9yIGNtZF9wZXJfbHVuIGlzIDYyIGJ1dCB0aGF0IHZh\n" - "bHVlIGNhbiBiZQ0Kb3ZlcnJpZGRlbiBieSBzZWxlY3RpbmcgYW5vdGhlciB2YWx1ZSBpbiAvZXRj\n" - "L2RlZmF1bHQvc3JwX2RhZW1vbi5jb25mLiBOb3RlOg0KYSBsb3dlciB2YWx1ZSBpcyBzZWxlY3Rl\n" - "ZCBpZiBhZnRlciBTUlAgbG9naW4gaXQgYmVjb21lcyBjbGVhciB0aGF0IHRoZSB0YXJnZXQNCnF1\n" - "ZXVlIGRlcHRoIGlzIGxvd2VyIHRoYW4gdGhlIGNtZF9wZXJfbHVuIHZhbHVlIHJlcXVlc3RlZCBi\n" - "eSB0aGUgdXNlci4gVGhpcw0KaXMgYSBwZXJmb3JtYW5jZSBvcHRpbWl6YXRpb24gYW5kIGF2b2lk\n" - "cyB0aGF0IHRoZSBTUlAgdGFyZ2V0IHN5c3RlbSBoYXMgdG8NCnNlbmQgYmFjayBCVVNZIHJlc3Bv\n" - bnNlcyB0byB0aGUgaW5pdGlhdG9yLg0KDQpCYXJ0Lg== + "On Sat, 2017-10-14 at 00:45 +0800, Ming Lei wrote:\n" + "> On Fri, Oct 13, 2017 at 04:31:04PM +0000, Bart Van Assche wrote:\n" + "> > On Sat, 2017-10-14 at 00:07 +0800, Ming Lei wrote:\n" + "> > > Actually it is in hot path, for example, lpfc and qla2xx's queue depth is 3,\n" + "> > \n" + "> > Sorry but I doubt whether that is correct. More in general, I don't know any modern\n" + "> > storage HBA for which the default queue depth is so low.\n" + "> \n" + "> You can grep:\n" + "> \n" + "> [ming@ming linux]$ git grep -n cmd_per_lun ./drivers/scsi/ | grep -E \"qla2xxx|lpfc\"\n" + "\n" + "Such a low queue depth will result in suboptimal performance for adapters\n" + "that communicate over a storage network. I think that's a bug and that both\n" + "adapters support much higher cmd_per_lun values.\n" + "\n" + "(+James Smart)\n" + "\n" + "James, can you explain us why commit 445cf4f4d2aa decreased LPFC_CMD_PER_LUN\n" + "from 30 to 3? Was that perhaps a workaround for a bug in a specific target\n" + "implementation?\n" + "\n" + "(+Himanshu Madhani)\n" + "\n" + "Himanshu, do you perhaps know whether it is safe to increase cmd_per_lun for\n" + "the qla2xxx initiator driver to the scsi_host->can_queue value?\n" + "\n" + "> Even SRP/IB isn't big too, just 32.\n" + "\n" + "The default value for ib_srp for cmd_per_lun is 62 but that value can be\n" + "overridden by selecting another value in /etc/default/srp_daemon.conf. Note:\n" + "a lower value is selected if after SRP login it becomes clear that the target\n" + "queue depth is lower than the cmd_per_lun value requested by the user. This\n" + "is a performance optimization and avoids that the SRP target system has to\n" + "send back BUSY responses to the initiator.\n" + "\n" + Bart. -3aa145dc2d49c04f63c47aea9aec537ace0650819df3cbe5612b83fb1176e167 +2a970e301460838f1f55c23b7d1093455ecb8c0852ff20910ee2a9a1f716daf6
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