Re: Wierd context-switching issue on Xeon
От | Magnus Naeslund(t) |
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Тема | Re: Wierd context-switching issue on Xeon |
Дата | |
Msg-id | 4085A895.6080403@fbab.net обсуждение исходный текст |
Ответ на | Re: Wierd context-switching issue on Xeon (Tom Lane <tgl@sss.pgh.pa.us>) |
Ответы |
Re: Wierd context-switching issue on Xeon
(Josh Berkus <josh@agliodbs.com>)
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Список | pgsql-performance |
Tom Lane wrote: > > Hmmm ... I've been able to reproduce the CS storm on a dual Athlon, > which seems to pretty much let the Xeon per se off the hook. Anybody > got a multiple Opteron to try? Totally non-Intel CPUs? > > It would be interesting to see results with non-Linux kernels, too. > > regards, tom lane I also tested on an dual Athlon MP Tyan Thunder motherboard (2xMP2800+, 2.5GB memory), and got the same high numbers. I then ran with kernel 2.6.5, it lowered them a little, but it's still some ping pong effect here. I wonder if this is some effect of the scheduler, maybe the shed frequency alone (100HZ vs 1000HZ). It would be interesting to see what a locking implementation ala FUTEX style would give on an 2.6 kernel, as i understood it that would work cross process with some work. The first file attached is kernel 2.4 running one process then starting up the other one. Same with second file, but with kernel 2.6... Regards Magnus procs -----------memory---------- ---swap-- -----io---- --system-- ----cpu---- r b swpd free buff cache si so bi bo in cs us sy id wa 1 0 0 1828408 27852 528852 0 0 0 0 317 557 50 0 50 0 1 0 0 1828408 27852 528852 0 0 0 0 293 491 50 0 49 0 1 0 0 1828400 27860 528852 0 0 0 16 399 709 50 0 50 0 1 0 0 1828400 27860 528852 0 0 0 0 350 593 50 0 49 0 2 0 0 1828400 27860 528852 0 0 0 0 349 608 50 0 50 0 1 0 0 1828400 27860 528852 0 0 0 0 109 412 50 0 50 0 1 0 0 1828400 27860 528852 0 0 0 0 101 92 50 0 50 0 1 0 0 1828392 27868 528852 0 0 0 16 104 96 50 0 50 0 1 0 0 1828392 27868 528852 0 0 0 0 101 103 50 0 50 0 2 0 0 1827408 27892 528852 0 0 8 48 113 61197 45 9 46 0 2 0 0 1827408 27892 528852 0 0 0 0 101 167237 41 27 32 0 procs -----------memory---------- ---swap-- -----io---- --system-- ----cpu---- r b swpd free buff cache si so bi bo in cs us sy id wa 4 0 0 1827408 27892 528852 0 0 0 0 101 166145 39 25 36 0 2 0 0 1827400 27900 528852 0 0 0 48 105 149406 42 19 40 0 3 0 0 1827400 27900 528852 0 0 0 0 101 157559 43 26 32 0 2 0 0 1827400 27900 528852 0 0 0 0 101 163813 46 24 30 0 2 0 0 1827400 27900 528852 0 0 0 0 101 156872 44 26 30 0 2 0 0 1827400 27900 528852 0 0 0 0 103 160722 45 28 28 0 2 0 0 1827392 27908 528852 0 0 0 16 104 158644 41 23 37 0 3 0 0 1827392 27908 528852 0 0 0 0 101 157534 42 25 33 0 2 0 0 1827392 27908 528852 0 0 0 0 101 160007 37 28 35 0 3 0 0 1827392 27908 528852 0 0 0 0 101 161852 45 24 31 0 3 0 0 1827392 27908 528852 0 0 0 0 101 161616 42 25 33 0 2 0 0 1827392 27916 528852 0 0 0 68 114 152144 44 25 31 0 2 0 0 1827384 27916 528852 0 0 0 0 101 156485 35 28 37 0 procs -----------memory---------- ---swap-- -----io---- --system-- ----cpu---- r b swpd free buff cache si so bi bo in cs us sy id wa 1 0 0 2436044 8844 90028 0 0 0 16 1010 235 50 0 50 0 1 0 0 2436108 8844 90028 0 0 0 0 1024 404 50 0 50 0 1 0 0 2436108 8844 90028 0 0 0 0 1008 199 50 0 50 0 1 0 0 2436108 8844 90028 0 0 0 0 1017 272 50 0 50 0 1 0 0 2436108 8844 90028 0 0 0 0 1013 253 50 0 50 0 1 1 0 2436108 8852 90020 0 0 0 16 1019 282 51 0 49 1 2 0 0 2435068 8852 90020 0 0 0 0 1005 23929 45 4 50 0 2 0 0 2435068 8852 90020 0 0 0 20 1008 95501 33 14 53 0 procs -----------memory---------- ---swap-- -----io---- --system-- ----cpu---- r b swpd free buff cache si so bi bo in cs us sy id wa 3 0 0 2435068 8852 90020 0 0 0 0 1002 103940 35 15 50 0 0 0 0 2435068 8852 90020 0 0 0 0 1003 104343 32 16 51 0 2 0 0 2435068 8860 90080 0 0 0 52 1006 102477 34 16 51 1 2 0 0 2435068 8860 90080 0 0 0 0 1002 92809 31 14 54 0 2 0 0 2435068 8860 90080 0 0 0 0 1002 100498 37 14 49 0 1 0 0 2435068 8860 90080 0 0 0 0 1002 108130 35 16 49 0 0 0 0 2435068 8860 90080 0 0 0 0 1002 94045 33 14 54 0 0 0 0 2435004 8868 90072 0 0 0 16 1005 104380 34 15 52 0 2 0 0 2435004 8868 90072 0 0 0 0 1002 100696 36 14 50 0 2 0 0 2435068 8868 90072 0 0 0 0 1002 98289 31 14 54 0 0 0 0 2435068 8868 90072 0 0 0 0 1002 97287 31 14 55 0 0 0 0 2435068 8868 90072 0 0 0 0 1002 92787 34 14 53 0 0 0 0 2435068 8876 90064 0 0 0 16 1005 98568 32 16 52 1 2 0 0 2435068 8876 90064 0 0 0 0 1003 107104 37 16 47 0
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