* Mel Gorman <mgorman@xxxxxxx> wrote: > Linear mapped reader on a 4-node machine with 64G RAM and 48 CPUs > > 4.1.0-rc6 4.1.0-rc6 > vanilla flushfull-v6 > Ops lru-file-mmap-read-elapsed 162.88 ( 0.00%) 120.81 ( 25.83%) > > 4.1.0-rc6 4.1.0-rc6 > vanillaflushfull-v6r5 > User 568.96 614.68 > System 6085.61 4226.61 > Elapsed 164.24 122.17 > > This is showing that the readers completed 25.83% faster with 30% less > system CPU time. From vmstats, it is known that the vanilla kernel was > interrupted roughly 900K times per second during the steady phase of the > test and the patched kernel was interrupts 180K times per second. > > The impact is lower on a single socket machine. > > 4.1.0-rc6 4.1.0-rc6 > vanilla flushfull-v6 > Ops lru-file-mmap-read-elapsed 25.43 ( 0.00%) 20.59 ( 19.03%) > > 4.1.0-rc6 4.1.0-rc6 > vanilla flushfull-v6 > User 59.14 58.99 > System 109.15 77.84 > Elapsed 27.32 22.31 > > It's still a noticeable improvement with vmstat showing interrupts went > from roughly 500K per second to 45K per second. Btw., I tried to compare your previous (v5) pfn-tracking numbers with these full-flushing numbers, and found that the IRQ rate appears to be the same: > > From vmstats, it is known that the vanilla kernel was interrupted roughly 900K > > times per second during the steady phase of the test and the patched kernel > > was interrupts 180K times per second. > > It's still a noticeable improvement with vmstat showing interrupts went from > > roughly 500K per second to 45K per second. ... is that because the batching limit in the pfn-tracking case was high enough to not be noticeable in the vmstat? In the full-flushing case (v6 without patch 4) the batching limit is 'infinite', we'll batch as long as possible, right? Or have I managed to get confused somewhere ... Thanks, Ingo -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>