Messages in this thread | | | Date | Tue, 28 Apr 2015 13:38:20 -0500 | From | nzimmer <> | Subject | Re: [PATCH 0/13] Parallel struct page initialisation v4 |
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On an older 8 TB box with lots and lots of cpus the boot time, as measure from grub to login prompt, the boot time improved from 1484 seconds to exactly 1000 seconds.
I have time on 16 TB box tonight and a 12 TB box thursday and will hopefully have more numbers then.
On 04/28/2015 11:06 AM, Pekka Enberg wrote: > On Tue, Apr 28, 2015 at 5:36 PM, Mel Gorman <mgorman@suse.de> wrote: >> Struct page initialisation had been identified as one of the reasons why >> large machines take a long time to boot. Patches were posted a long time ago >> to defer initialisation until they were first used. This was rejected on >> the grounds it should not be necessary to hurt the fast paths. This series >> reuses much of the work from that time but defers the initialisation of >> memory to kswapd so that one thread per node initialises memory local to >> that node. >> >> After applying the series and setting the appropriate Kconfig variable I >> see this in the boot log on a 64G machine >> >> [ 7.383764] kswapd 0 initialised deferred memory in 188ms >> [ 7.404253] kswapd 1 initialised deferred memory in 208ms >> [ 7.411044] kswapd 3 initialised deferred memory in 216ms >> [ 7.411551] kswapd 2 initialised deferred memory in 216ms >> >> On a 1TB machine, I see >> >> [ 8.406511] kswapd 3 initialised deferred memory in 1116ms >> [ 8.428518] kswapd 1 initialised deferred memory in 1140ms >> [ 8.435977] kswapd 0 initialised deferred memory in 1148ms >> [ 8.437416] kswapd 2 initialised deferred memory in 1148ms >> >> Once booted the machine appears to work as normal. Boot times were measured >> from the time shutdown was called until ssh was available again. In the >> 64G case, the boot time savings are negligible. On the 1TB machine, the >> savings were 16 seconds. > FWIW, > > Acked-by: Pekka Enberg <penberg@kernel.org> > > for the whole series. > > - Pekka
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