Re: Another Linux performance anomaly with 1+ GB files
Scott Laird (laird@pacificrim.net)
Wed, 12 Nov 1997 12:15:15 -0800
In message <346A0F5B.CE471545@star.net>, Bill Hawes writes:
>Scott Laird wrote:
>
>> The only time I've seen the slowdowns, they've occurred during a read
>> from the 4k filesystem. I'm not sure if the WCHAN reported by ps is
>> accurate or not, but it was reporting 1261d9, which is in the middle
>> of try_to_free_buffers, according to my System.map.
>
>There aren't supposed to be any blocking operations in
>try_to_free_buffer. Could the task perhaps be stuck in a tight loop
>repeatedly calling try_to_free_buffer()? The next time it gets stuck,
>try hitting alt-scroll-lock a few times to get the current address, and
>then look this up your System.map. If the address is changing but
>usually in try_to_free_buffer(), the system is probably looking for
>memory and repeatedly trying to free buffers.
Sure. I haven't seen any problems yet with 2.1.62, but I should be
able to drop back to 2.0.x either tonight or tomorrow night for a few
tests. I'll see what happens then.
Scott