Messages in this thread | | | Date | Mon, 13 May 2013 09:40:08 +0100 | From | Mel Gorman <> | Subject | Re: [Query] Performance degradation with memory compaction (on QC chip-set) |
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On Sun, May 12, 2013 at 08:00:26PM -0700, PINTU KUMAR wrote: > Dear Mel Gorman, > > I have one question about memory compaction. > Kernel version: kernel-3.4 (ARM) > Chipset: Qual-Comm MSM8930 dual-core. > > We wanted to enable CONFIG_COMPACTION for our product with kernel-3.4. > But QC commented that, enabling compaction on their chip-set is causing performance degradation for some streaming scenarios (from the beginning). > > I wanted to know is this possible always? > We used compaction with exynos processor and did not observe any performance degradation. >
I suspect one of their drivers are using high-order allocations and hitting compaction as a result. Compaction is not guaranteed to cause overhead but if it's in use then the scanning and copying overhead can cause problems.
> Please let me know your comments. > It will be helpful to decide on enabling compaction or not. >
Depends on workload and drivers.
-- Mel Gorman SUSE Labs
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