-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 3/24/15 10:43 AM, Hannes Reinecke wrote:
On 03/24/2015 03:40 PM, Jeff Mahoney wrote:
On 3/24/15 10:21 AM, Jiri Slaby wrote:
On 03/24/2015, 02:20 PM, David Sterba wrote:
Hi,
currently the scsi-mq is set to Y, since 3.18-rc1 merge. The option enables a feature that makes advantage of enterprise-class storage. It's known not to perform well on slower devices [1] and lacks scheduler support.
We'll set the option to N in our stable kernels.
Ok, but set the same on master too. The two kernels should be identical at every .0 release.
No, please don't. I'm in the middle of writing a longer reply to this because I think it's the wrong approach.
Same here. If scsi-mq gives a degraded performance we should disable it on a per-driver basis, leaving the 'high-end' HBA free to profit from this.
I'll gladly do a patch for this ...
It doesn't even look like it would be that involved. There is already Scsi_Host->use_blk_mq. That's keyed off of scsi_mod.use_blk_mq and scsi_host_template->disable_blk_mq. The latter option obviously doesn't help much. It's more of an escape hatch if a particular HBA is well and truly hosed WRT mq. If we were to key Scsi_Host->use_blk_mq off of a more granular switch, that should help. But really what I'd like to see is granularity on a per-device basis or, perhaps more usefully, a way to shim classic block onto the end of blk-mq. blk-mq is lightweight enough and the target use cases are heavyweight enough that the overhead of passing through blk-mq might not matter. - -Jeff - -- Jeff Mahoney SUSE Labs -----BEGIN PGP SIGNATURE----- Version: GnuPG/MacGPG2 v2.0.19 (Darwin) iQIcBAEBAgAGBQJVEXvcAAoJEB57S2MheeWyXJQQAMB5Kzje+hGFL9pJOvZv2Ze/ uBVuSqKt9Kw8NPW+1tXXioKlrrsfhbWq4VmffC3LevefMsDRDa2DenhTMaBbA3te thKTDDip7gS9eibOAjgh46I1ZTu4hSmCWQSy7dYCVsymEg6pd82fGYH2LMUFuVVN zTEcIlAj31J1IgBa0+q8F7reavraHxR4cIq9ukeVbWDOniXw9BH+z/km3D7wh2wm poY0KG+zHVTe63G00ElGdYphdhuSDTaCAJwt3iif6Y5htclkQIT2lRyukdaya7NU sDfDwErJNnvlWHCouzEQ0tTdPljsy5Fcy20B737csiXwHrgo3w8POhC+LkNUZvcQ nXy1HGTMCsWuSd38wd/PgJhC3Jx/xFTws7MjXgY140pKMZiWd60ZvYH6xNX/flDr T/aGh+PSPaYJNNeho/xEfNrQ4jSbg4wDjr8iV2bKkYyuuV25nOYvzQ+0pu5oL+zq bxHauXMbwVwrdqx0y3W6KQLQsDS2veNhO4GAgXxB0ICNTOse118lVc4ry7PQLo98 qpmj8P+3ZZe3J4A33bF5LYTNFgWw+h5RqXlsv8fm5Xq6OdOuA1o0q9tVT4b5SyII S6LiztL+IKFuVD66VaMCPGFhDzR+kwFK3CFiMVG9WdERof7zCYM6zOaHXzRXiz2D Swa3oSqPu4fo8+jqdPjI =/ZtX -----END PGP SIGNATURE----- -- To unsubscribe, e-mail: opensuse-kernel+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-kernel+owner@opensuse.org