Re: [PATCH 06/13] writeback: bdi write bandwidth estimation

[Wu Fengguang]

btw, I noticed that the same dd is constantly running from different
CPUs.

It's multi-core CPUs on the same socket, so should not be a big
problem. I'll test NUMA setup later.

This trace is for single dd case. 

dd-2893  [005]  3535.182111: balance_dirty_pages: bdi=8:0
dd-2893  [001]  3535.230125: balance_dirty_pages: bdi=8:0
dd-2893  [005]  3535.274805: balance_dirty_pages: bdi=8:0
dd-2893  [005]  3535.289337: balance_dirty_pages: bdi=8:0
dd-2893  [005]  3535.497863: balance_dirty_pages: bdi=8:0
dd-2893  [005]  3535.585510: balance_dirty_pages: bdi=8:0
dd-2893  [005]  3535.622001: balance_dirty_pages: bdi=8:0
dd-2893  [005]  3535.645003: balance_dirty_pages: bdi=8:0
dd-2893  [001]  3535.659603: balance_dirty_pages: bdi=8:0
dd-2893  [001]  3535.669497: balance_dirty_pages: bdi=8:0
dd-2893  [001]  3535.731294: balance_dirty_pages: bdi=8:0
dd-2893  [001]  3535.785879: balance_dirty_pages: bdi=8:0
dd-2893  [001]  3535.827724: balance_dirty_pages: bdi=8:0
dd-2893  [001]  3535.853108: balance_dirty_pages: bdi=8:0
dd-2893  [001]  3535.875667: balance_dirty_pages: bdi=8:0
dd-2893  [005]  3535.895731: balance_dirty_pages: bdi=8:0
dd-2893  [005]  3535.914920: balance_dirty_pages: bdi=8:0
dd-2893  [005]  3535.925765: balance_dirty_pages: bdi=8:0
dd-2893  [005]  3535.935545: balance_dirty_pages: bdi=8:0
dd-2893  [001]  3536.015888: balance_dirty_pages: bdi=8:0
dd-2893  [001]  3536.085571: balance_dirty_pages: bdi=8:0

Here is another run (1-dd):

dd-3014  [001]  1248.388001: balance_dirty_pages: bdi=8:0 bdi_dirty=122640 avg_dirty=122643 
dd-3014  [002]  1248.465999: balance_dirty_pages: bdi=8:0 bdi_dirty=122400 avg_dirty=122625 
dd-3014  [007]  1248.531451: balance_dirty_pages: bdi=8:0 bdi_dirty=122240 avg_dirty=122600 
dd-3014  [007]  1248.599260: balance_dirty_pages: bdi=8:0 bdi_dirty=122000 avg_dirty=122561 
dd-3014  [003]  1248.667152: balance_dirty_pages: bdi=8:0 bdi_dirty=120840 avg_dirty=122447 
dd-3014  [007]  1248.734848: balance_dirty_pages: bdi=8:0 bdi_dirty=120640 avg_dirty=122328 
dd-3014  [007]  1248.798652: balance_dirty_pages: bdi=8:0 bdi_dirty=120440 avg_dirty=122210 
dd-3014  [007]  1248.862456: balance_dirty_pages: bdi=8:0 bdi_dirty=120240 avg_dirty=122087 
dd-3014  [003]  1248.926280: balance_dirty_pages: bdi=8:0 bdi_dirty=120040 avg_dirty=121960 
dd-3014  [005]  1248.986091: balance_dirty_pages: bdi=8:0 bdi_dirty=119760 avg_dirty=121832 
dd-3014  [005]  1249.045841: balance_dirty_pages: bdi=8:0 bdi_dirty=119600 avg_dirty=121702 

And this 100 dd case looks much better (however it's not always the case):

dd-2775  [007]   454.844907: balance_dirty_pages: bdi=8:0 bdi_dirty=104040 avg_dirty=409468930 
dd-2775  [007]   455.048108: balance_dirty_pages: bdi=8:0 bdi_dirty=103800 avg_dirty=409676055 
dd-2775  [007]   455.252347: balance_dirty_pages: bdi=8:0 bdi_dirty=103720 avg_dirty=409676055 
dd-2775  [007]   455.455538: balance_dirty_pages: bdi=8:0 bdi_dirty=103800 avg_dirty=409676055 
dd-2775  [007]   455.658597: balance_dirty_pages: bdi=8:0 bdi_dirty=103880 avg_dirty=409676055 
dd-2775  [007]   455.862631: balance_dirty_pages: bdi=8:0 bdi_dirty=103760 avg_dirty=410276387 
dd-2775  [007]   456.068149: balance_dirty_pages: bdi=8:0 bdi_dirty=103800 avg_dirty=410276387 
dd-2775  [007]   456.266729: balance_dirty_pages: bdi=8:0 bdi_dirty=103760 avg_dirty=410833633 
dd-2775  [007]   456.470184: balance_dirty_pages: bdi=8:0 bdi_dirty=103840 avg_dirty=410833633 
dd-2775  [007]   456.668919: balance_dirty_pages: bdi=8:0 bdi_dirty=103960 avg_dirty=410833633 
dd-2775  [007]   456.872522: balance_dirty_pages: bdi=8:0 bdi_dirty=103880 avg_dirty=411001977 
dd-2775  [007]   457.070753: balance_dirty_pages: bdi=8:0 bdi_dirty=104040 avg_dirty=411001977 
dd-2775  [007]   457.275970: balance_dirty_pages: bdi=8:0 bdi_dirty=103960 avg_dirty=411227747 
dd-2775  [007]   457.473736: balance_dirty_pages: bdi=8:0 bdi_dirty=103920 avg_dirty=411534633 
dd-2775  [007]   457.677204: balance_dirty_pages: bdi=8:0 bdi_dirty=103920 avg_dirty=412195106 
dd-2775  [007]   457.881156: balance_dirty_pages: bdi=8:0 bdi_dirty=104040 avg_dirty=412195106 
dd-2775  [007]   458.085173: balance_dirty_pages: bdi=8:0 bdi_dirty=103920 avg_dirty=412295260 
dd-2775  [007]   458.285146: balance_dirty_pages: bdi=8:0 bdi_dirty=104000 avg_dirty=412295260 
dd-2775  [007]   458.490109: balance_dirty_pages: bdi=8:0 bdi_dirty=103960 avg_dirty=412789184 
dd-2775  [007]   458.692230: balance_dirty_pages: bdi=8:0 bdi_dirty=103960 avg_dirty=412789184 

Thanks,
Fengguang
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