https://jira.whamcloud.com This file is an XML representation of an issue en-us 9.4.14 940014 05-12-2023 https://jira.whamcloud.com/browse/LU-3059 Lustre <p>Before:</p> <div class="preformatted panel" style="border-width: 1px;"><div class="preformattedContent panelContent"> <pre>struct lod_object { struct dt_object ldo_obj; /* 0 88 */ /* --- cacheline 1 boundary (64 bytes) was 24 bytes ago --- */ __u16 ldo_stripenr; /* 88 2 */ __u16 ldo_layout_gen; /* 90 2 */ __u32 ldo_stripe_size; /* 92 4 */ char * ldo_pool; /* 96 8 */ struct dt_object * * ldo_stripe; /* 104 8 */ int ldo_stripes_allocated; /* 112 4 */ unsigned int ldo_striping_cached:1; /* 116:31 4 */ unsigned int ldo_def_striping_set:1; /* 116:30 4 */ /* XXX 30 bits hole, try to pack */ __u32 ldo_def_stripe_size; /* 120 4 */ __u16 ldo_def_stripenr; /* 124 2 */ __u16 ldo_def_stripe_offset; /* 126 2 */ /* --- cacheline 2 boundary (128 bytes) --- */ mdsno_t ldo_mds_num; /* 128 4 */ /* size: 136, cachelines: 3, members: 13 */ /* bit holes: 1, sum bit holes: 30 bits */ /* padding: 4 */ /* last cacheline: 8 bytes */ }; </pre> </div></div> <p>After:</p> <div class="preformatted panel" style="border-width: 1px;"><div class="preformattedContent panelContent"> <pre>struct lod_object { struct dt_object ldo_obj; /* 0 88 */ /* --- cacheline 1 boundary (64 bytes) was 24 bytes ago --- */ __u16 ldo_stripenr; /* 88 2 */ __u16 ldo_layout_gen; /* 90 2 */ __u32 ldo_stripe_size; /* 92 4 */ char * ldo_pool; /* 96 8 */ struct dt_object * * ldo_stripe; /* 104 8 */ unsigned int ldo_stripes_allocated:16; /* 112:16 4 */ unsigned int ldo_striping_cached:1; /* 112:15 4 */ unsigned int ldo_def_striping_set:1; /* 112:14 4 */ /* XXX 14 bits hole, try to pack */ __u32 ldo_def_stripe_size; /* 116 4 */ __u16 ldo_def_stripenr; /* 120 2 */ __u16 ldo_def_stripe_offset; /* 122 2 */ mdsno_t ldo_mds_num; /* 124 4 */ /* --- cacheline 2 boundary (128 bytes) --- */ /* size: 128, cachelines: 2, members: 13 */ /* bit holes: 1, sum bit holes: 14 bits */ }; </pre> </div></div> LU-3059

shrink lod_object to 128 bytes

Bug Minor Resolved Fixed John Hammond John Hammond lod Thu, 28 Mar 2013 18:34:01 +0000 Mon, 2 Jun 2014 15:54:25 +0000 Tue, 23 Jul 2013 14:30:11 +0000 Lustre 2.4.0 Lustre 2.4.0 Lustre 2.5.0 Lustre 2.6.0 0 2 <p>we could <b>also</b> turn ldo_stripe + ldo_stripes_allocated + ldo_striping_cached + ldo_def_striping_set (probably more?) a separately allocated structure.<br/> because most of time we don't use those fields at all.</p> <p>then use SLAB to pack ldo_object structures better in a page.</p> <p>Please see <a href="http://review.whamcloud.com/5878" class="external-link" target="_blank" rel="nofollow noopener">http://review.whamcloud.com/5878</a>.</p> <p>But then there definitely needs to be a lock in lod_object.</p> <p><a href="http://review.whamcloud.com/5890" class="external-link" target="_blank" rel="nofollow noopener">http://review.whamcloud.com/5890</a> shrink lu_object by 16 bytes on x86_64</p> <p><a href="http://review.whamcloud.com/5892" class="external-link" target="_blank" rel="nofollow noopener">http://review.whamcloud.com/5892</a> shrink dt_object by 8 bytes on x86_64</p> <p><a href="http://review.whamcloud.com/#change,5920" class="external-link" target="_blank" rel="nofollow noopener">http://review.whamcloud.com/#change,5920</a> obdclass: use a dummy structure for lu_ref_link</p> <p>All four patches landed to master. On 2.4.52-37-g6350af1 compiled for x86_64 we have the following object sizes:</p> <div class="preformatted panel" style="border-width: 1px;"><div class="preformattedContent panelContent"> <pre>lu_object_header 88 cl_object_header 152 lu 40 cl 56 md 56 dt 64 mdd 80 lod 112 osd_ldiskfs 176 osp 200 lov 224 ccc 248 mdt 256 osc 272 </pre> </div></div> Related LU-2789 Business Value -7.0 Development Rank 1|hzvmlr: Rank (Obsolete) 7456 Severity