On Thu, 16 Apr 2009, Sebastian Hagedorn wrote: > --On 16. April 2009 10:58:15 +1000 Rob Mueller <robm@xxxxxxxxxxx> wrote: > >>> http://blog.fastmail.fm/2007/09/21/reiserfs-bugs-32-bit-vs-64-bit-kernel >>> s-cache-vs-inode-memory/ >>> >>> Anyone have any specific thoughts? Is there any other benefit we might >>> see from large memory allocation in 64-bit architecture? >> >> Given that I wrote that blog post, I can only tell you that in our >> environment, 64-bit kernels made a big difference. > > I wonder if ext3 behaves differently, Red Hat's 32-bit behaves differently, > or if something altogether different is going on. We are currently running > RHEL 3 in 32-bit mode, our servers have 16 GB, and most of it is used for > caching: > > # free > total used free shared buffers cached > Mem: 16214344 16197612 16732 0 86944 13415172 > -/+ buffers/cache: 2695496 13518848 > Swap: 4192944 8436 4184508 > > So it would seem that a 64-bit kernel wouldn't improve on that, right? Or is > that a difference between 2.4 and 2.6? That's interesting, and not what I expected. :) What does "cat /proc/meminfo" show? My 64-bit kernel running cyrus has: MemTotal: 4051576 kB MemFree: 31452 kB Buffers: 478716 kB Cached: 2471240 kB SwapCached: 0 kB Active: 1562596 kB Inactive: 1768236 kB SwapTotal: 2000052 kB SwapFree: 1999396 kB Dirty: 1484 kB Writeback: 40 kB AnonPages: 380888 kB Mapped: 68340 kB Slab: 601940 kB SReclaimable: 500604 kB SUnreclaim: 101336 kB PageTables: 41220 kB NFS_Unstable: 0 kB Bounce: 0 kB CommitLimit: 4025840 kB Committed_AS: 659524 kB VmallocTotal: 34359738367 kB VmallocUsed: 280476 kB VmallocChunk: 34359457535 kB HugePages_Total: 0 HugePages_Free: 0 HugePages_Rsvd: 0 HugePages_Surp: 0 Hugepagesize: 2048 kB On an older system running a 32-bit "686" kernel, it shows: MemTotal: 2076312 kB MemFree: 73008 kB Buffers: 61916 kB Cached: 1512400 kB SwapCached: 0 kB Active: 429292 kB Inactive: 1467944 kB HighTotal: 1179392 kB HighFree: 8400 kB LowTotal: 896920 kB LowFree: 64608 kB SwapTotal: 2000052 kB SwapFree: 1999988 kB Dirty: 140 kB Writeback: 0 kB AnonPages: 322960 kB Mapped: 24180 kB Slab: 77336 kB SReclaimable: 45836 kB SUnreclaim: 31500 kB PageTables: 5900 kB NFS_Unstable: 12 kB Bounce: 0 kB CommitLimit: 3038208 kB Committed_AS: 598964 kB VmallocTotal: 114680 kB VmallocUsed: 3936 kB VmallocChunk: 110188 kB HugePages_Total: 0 HugePages_Free: 0 HugePages_Rsvd: 0 HugePages_Surp: 0 Hugepagesize: 4096 kB Note the HighTotal, HighFree, LowTotal, and LowFree lines that are not present in a 64-bit kernel. Andy ---- Cyrus Home Page: http://cyrusimap.web.cmu.edu/ Cyrus Wiki/FAQ: http://cyrusimap.web.cmu.edu/twiki List Archives/Info: http://asg.web.cmu.edu/cyrus/mailing-list.html
