Hi. We have severe issues getting a Intel(R) Xeon(R) CPU E7-8857 v2 @ 3.00GHz 48 cores server to perform nice.
We have just setup a new server for a PostgreSQL database with 3TB of memory, primarily for disk-io-caching. The server is running Ubuntu 12.04 on kernel 3.13.0-43-generic. The only change is that we have: echo never > /sys/kernel/mm/transparent_hugepage/enabled We have "system load spikes" on it. So it occationally are peaking at 80-90% system load for minutes and then migrating back to "normal". When it happens all other activity suffers. Before disabling hugepages, the system pretty much went to a complete stall when memory pressure occoured. sar reports 13:05:01 CPU %user %nice %system %iowait %steal %idle 16:25:01 all 11.20 0.00 2.11 3.75 0.00 82.94 16:30:01 all 12.55 0.00 2.67 3.63 0.00 81.15 16:35:01 all 12.24 0.00 3.68 3.61 0.00 80.47 16:40:01 all 11.74 0.00 2.31 3.46 0.00 82.48 16:45:01 all 15.12 0.00 4.31 3.85 0.00 76.71 16:50:01 all 43.04 0.00 8.89 5.24 0.00 42.82 16:55:01 all 46.14 0.00 13.53 5.29 0.00 35.03 17:05:01 all 27.24 0.00 40.16 3.77 0.00 28.83 17:10:01 all 17.24 0.00 57.76 2.68 0.00 22.32 17:15:01 all 44.89 0.00 11.14 4.44 0.00 39.53 17:20:03 all 29.73 0.00 33.77 3.99 0.00 32.51 In above workload it is "only" running pg_dump and pg_restore with 2 instances of postgresql running. No network/nfs/etc at the same time and not more than 48 processes active at the same time. Any suggestions/ideas for how/what to improve are greatly welcome. Both in terms of tunables and potential fixes in kernels. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
