-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 >From what I understand, you probably got most of your reduction from co-locating your memory to the right NUMA nodes. tcmalloc/jemalloc should be much higher in performance because of how they hold memory in thread pools (less locking to allocate memory) and they try much harder to reuse dirty free pages so memory stays within the thread again reducing locking for memory allocations. I would do some more testing along with what Ben Hines mentioned about overall client performance. - ---------------- Robert LeBlanc GPG Fingerprint 79A2 9CA4 6CC4 45DD A904 C70E E654 3BB2 FA62 B9F1 On Wed, Jun 24, 2015 at 11:25 AM, Jan Schermer wrote: There were essentialy three things we had to do for such a drastic drop 1) recompile CEPH —without-tcmalloc 2) pin the OSDs to a set of a specific NUMA zone - we had this for a long time and it really helped 3) migrate the OSD memory to the correct CPU with migratepages - we will use cgroups in the future for this, should make life easier and is the only correct solution It is similiar to the effect of just restarting the OSD, but much better - since we immediately see hundreds of connections on a freshly restarted OSD (and in the benchmark the tcmalloc issue manifested with just two clients in parallel) I’d say we never saw the raw performance with tcmalloc (undegraded), but it was never this good - consistently low latencies, much smaller spikes when something happens and much lower CPU usage (about 50% savings but we’re also backfilling a lot on the background). Workloads are faster as well - like reweighting OSDs on that same node was much (hundreds of percent) faster. So far the effect has been drastic. I wonder why tcmalloc was even used when people are having problems with it? The glibc malloc seems to work just fine for us. The only concerning thing is the virtual memory usage - we are over 400GB VSS with a few OSDs. That doesn’t hurt anything, though. Jan On 24 Jun 2015, at 18:46, Robert LeBlanc wrote: - -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 Did you see what the effect of just restarting the OSDs before using tcmalloc? I've noticed that there is usually a good drop for us just by restarting them. I don't think it is usually this drastic. - - ---------------- Robert LeBlanc GPG Fingerprint 79A2 9CA4 6CC4 45DD A904 C70E E654 3BB2 FA62 B9F1 On Wed, Jun 24, 2015 at 2:08 AM, Jan Schermer wrote: Can you guess when we did that? Still on dumpling, btw... http://www.zviratko.net/link/notcmalloc.png Jan _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com - -----BEGIN PGP SIGNATURE----- Version: Mailvelope v0.13.1 Comment: https://www.mailvelope.com wsFcBAEBCAAQBQJVit75CRDmVDuy+mK58QAAmjcP/jU+wyohdwKDP+FHDAgJ DcqdB5aPG2AM79iLcYUub5bQjdNJpcWN/hyZcNdF3aSzEV3aY6jIqu9OpOIB c2fIzfGOoczzW/FEf7qKRVGpxaQL21Sw1LpwMEscNe0ETz9HMHoaAnBO9IFn nUEOCdEpRBO5W1rWwNAx9EVnOUPklb7vVEpY23sgtHhQSprb9oeO8D99AMRz /RhdHKlRDgHBjun/stCiR6lFuvBUx0GBmyaMuO5rfsLGRIkySLv++3CLQI6X NCt/MjYwTTNNfO/y/MjkiV/j+Cm1G1lcjlgbDjilf7bgf8/7W2vJa1sMtaA4 xJL+PpZxiKcGSdC96B+EBYxLhLcwsNpbfq7uxQOkIspa66mkIMAVzJgt4DFL Ca+UY3ODA26VtWF5U/hkdupgld+YSxXTyJakeShrBSFAX0a4cygV9Ll7SIhO IDS+0Mbur0IGzIWRgtCQhRXsc7wn3IoIovqe8Nfk4xupeoK2P5UHO1rW9pWy Jwj5PXieDqxgx8RKlulN1bCbSgTaEdveTiqqVxlnM9L0MhgesuB8vkpHbsqn mYJHNzU7ghU89xLnRuia9rBlpjw4OzagfowAJTH3UnaO67kxES+IWO8onQbN RhY0QR5cB5rVSjYkzzlsuLM17fQPcT8++yMarKdsrr6WIGppXUFFdATAqIaY DHD1 =goL4 - -----END PGP SIGNATURE----- -----BEGIN PGP SIGNATURE----- Version: Mailvelope v0.13.1 Comment: https://www.mailvelope.com wsFcBAEBCAAQBQJViuu0CRDmVDuy+mK58QAASzoQAIf4Lj/jA2yl2XMS7RAW FmgK8rsf2iyzg6UQMmobFw0oWTb/0T4AscXlZIE7dhGUi6m6UHWBPB7P6YBZ UQ2eJqzcaK1Jf/flfTZajWB2z2CSYpuwbPYaQ8SqKoyauEjKgD092/LUfKL3 TP5z7SdhZ8/HmzT2qFUdYuAQ+WvD3rgdJtkblFgItM+bqKmhibiZr3KHzXoU j5Ob61AsR6/s3hgWJ09uAghqB8SNsxJ0u7R5RnaiS2VWkHSHTrdiTwd/ONlL anBnKljTgkCSqS3RoPVB74qlqhDxlDnwRYvKrxurcikaI3tZ17xt4UvCc9yP RRH6M8aU1+7itOxu8DyOeZ+9Ev5/H6i5LwtrnN2pHaN9s0tWRKwzt5HQEYhE ceoyui+EtpN8zzqs9ryIGvHL3KB1bmL+0WWO4RlT8NwodsSge3Yga8KUMa07 8+dh0VGUywGEmxMg2VWPyvKf/keOiWHHi4UDJRgXJdnBjH/+4Yebva7TJ2b9 Ch0r8JL00nbJCBb78dvw59XiFUJBFT5WfgItmbfjX2SI+srFaDXFKtGSjnFi MK4gE7DA70tKgP+xwpw3Eou7rDzxogqxnV54BlNzvbokbfiDAZ/ARL7CtC/1 SnBxzEaliaJnBHKSgwOyP9sxz+QKMxty2ZTSmCnBUxKRK9O2hNSzFf6+1heT yQ3L =DreJ -----END PGP SIGNATURE-----
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