bmalloc: Don't use a whole page for metadata
Created attachment 271878 [details] Patch
Perf numbers on Mac: Baseline Patch Δ Execution Time: churn 80ms 77ms ^ 1.04x faster list_allocate 77ms 77ms tree_allocate 83ms 83ms tree_churn 87ms 86ms ^ 1.01x faster fragment 94ms 96ms ! 1.02x slower fragment_iterate 65ms 63ms ^ 1.03x faster medium 208ms 206ms ^ 1.01x faster big 157ms 163ms ! 1.04x slower facebook 421ms 419ms ^ 1.0x faster reddit 92ms 91ms ^ 1.01x faster flickr 98ms 98ms theverge 117ms 116ms ^ 1.01x faster message_one 220ms 219ms ^ 1.0x faster message_many 119ms 119ms churn --parallel 39ms 38ms ^ 1.03x faster list_allocate --parallel 70ms 76ms ! 1.09x slower tree_allocate --parallel 84ms 87ms ! 1.04x slower tree_churn --parallel 85ms 85ms fragment --parallel 51ms 53ms ! 1.04x slower fragment_iterate --parallel 32ms 32ms medium --parallel 197ms 196ms ^ 1.01x faster big --parallel 135ms 134ms ^ 1.01x faster <geometric mean> 99ms 100ms ! 1.0x slower <arithmetic mean> 119ms 119ms ! 1.0x slower <harmonic mean> 85ms 85ms ! 1.0x slower Peak Memory: churn 812kB 800kB ^ 1.01x smaller list_allocate 2,096kB 2,096kB tree_allocate 5,504kB 5,484kB ^ 1.0x smaller tree_churn 4,804kB 4,792kB ^ 1.0x smaller fragment 7,020kB 6,988kB ^ 1.0x smaller fragment_iterate 25,704kB 25,580kB ^ 1.0x smaller medium 1,070,440kB 1,068,404kB ^ 1.0x smaller big 1,062,472kB 1,060,444kB ^ 1.0x smaller facebook 74,444kB 73,896kB ^ 1.01x smaller reddit 13,840kB 13,844kB ! 1.0x bigger flickr 25,788kB 25,788kB theverge 27,004kB 26,928kB ^ 1.0x smaller message_one 4,524kB 4,696kB ! 1.04x bigger message_many 4,928kB 4,936kB ! 1.0x bigger churn --parallel 944kB 944kB list_allocate --parallel 2,224kB 2,212kB ^ 1.01x smaller tree_allocate --parallel 3,328kB 3,372kB ! 1.01x bigger tree_churn --parallel 3,024kB 3,012kB ^ 1.0x smaller fragment --parallel 7,172kB 7,140kB ^ 1.0x smaller fragment_iterate --parallel 25,872kB 25,688kB ^ 1.01x smaller medium --parallel 1,067,448kB 1,066,516kB ^ 1.0x smaller big --parallel 1,058,608kB 1,057,128kB ^ 1.0x smaller <geometric mean> 16,554kB 16,542kB ^ 1.0x smaller <arithmetic mean> 204,455kB 204,122kB ^ 1.0x smaller <harmonic mean> 4,241kB 4,231kB ^ 1.0x smaller Memory at End: churn 412kB 396kB ^ 1.04x smaller list_allocate 412kB 408kB ^ 1.01x smaller tree_allocate 484kB 468kB ^ 1.03x smaller tree_churn 464kB 452kB ^ 1.03x smaller fragment 476kB 456kB ^ 1.04x smaller fragment_iterate 716kB 660kB ^ 1.08x smaller medium 6,652kB 4,612kB ^ 1.44x smaller big 6,628kB 4,596kB ^ 1.44x smaller facebook 3,520kB 3,312kB ^ 1.06x smaller reddit 2,200kB 2,228kB ! 1.01x bigger flickr 3,204kB 3,232kB ! 1.01x bigger theverge 3,264kB 3,244kB ^ 1.01x smaller message_one 692kB 680kB ^ 1.02x smaller message_many 1,080kB 1,220kB ! 1.13x bigger churn --parallel 544kB 540kB ^ 1.01x smaller list_allocate --parallel 592kB 608kB ! 1.03x bigger tree_allocate --parallel 716kB 716kB tree_churn --parallel 1,192kB 1,144kB ^ 1.04x smaller fragment --parallel 1,316kB 1,300kB ^ 1.01x smaller fragment_iterate --parallel 948kB 828kB ^ 1.14x smaller medium --parallel 6,776kB 4,740kB ^ 1.43x smaller big --parallel 6,744kB 4,740kB ^ 1.42x smaller <geometric mean> 1,331kB 1,228kB ^ 1.08x smaller <arithmetic mean> 2,229kB 1,845kB ^ 1.21x smaller <harmonic mean> 899kB 870kB ^ 1.03x smaller
Comment on attachment 271878 [details] Patch r=me
Committed r196873: <http://trac.webkit.org/changeset/196873>