Re: [PATCH 01/13] writeback: IO-less balance_dirty_pages()

[Wu Fengguang]

> BEHAVIOR CHANGE
> ===============
> 
> Users will notice that the applications will get throttled once the
> crossing the global (background + dirty)/2=15% threshold. For a single
> "cp", it could be soft throttled at 2*bdi->write_bandwidth around 15%

s/2/8/

Sorry, the initial soft throttle bandwidth for "cp" is about 8 times
of bdi bandwidth when reaching 15% dirty pages.

> dirty pages, and be balanced at speed bdi->write_bandwidth around 17.5%
> dirty pages. Before patch, the behavior is to just throttle it at 17.5%
> dirty pages.
> 
> Since the task will be soft throttled earlier than before, it may be
> perceived by end users as performance "slow down" if his application
> happens to dirty more than ~15% memory.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/