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On futher analysis I figured that root cause of the issue is >> the frequent pcp high order flushes. During a 20sec iperf3 run >> I observed on avg 5 pcp high order flushes in kernel v6.6, whereas, in >> v6.7, I observed about 170 pcp high order flushes. >> Tracing pcp->free_count, I figured with the patch v1 (patch I suggested >> earlier) free_count is going into negatives which reduces the number of >> times free_high heuristics is triggered hence reducing the high order >> flushes. >> >> As Ying Huang Suggested, it helps the performance on increasing the >> batch size >> for free_high heuristics. I tried different scaling factors to find best >> suitable batch value for free_high heuristics, >> >> >>             score    # free_high >> -----------        -----    ----------- >> v6.6 (base)        100         4 >> v6.12 (batch*1)         69          170 >> batch*2             69          150 >> batch*4             74          101 >> batch*5            100           53 >> batch*6            100           36 >> batch*8            100        3 >>    scaling batch for free_high heuristics with a factor of 5 restores >> the >> performance. > > Hello Nikhil, > > Thanks for looking further on this. But from design standpoint, > how a batch-size of 5 is helping here is not clear (Andrew's original > question). > > Any case can you post the patch-set in a new email so that the below > patch is not lost in discussion thread? Hi Raghavendra, Thanks, I have posted the patch-set in a new email link: https://lore.kernel.org/linux-mm/20250325171915.14384-1-nikhil.dhama@amd.com/ with a better explanation on  how scaling batch is helping here. Thanks, Nikhil