Messages in this thread | | | Date | Fri, 24 Aug 2001 20:12:42 -0300 (BRST) | From | Rik van Riel <> | Subject | Re: [resent PATCH] Re: very slow parallel read performance |
| |
On Fri, 24 Aug 2001, Gérard Roudier wrote:
> The larger the read-ahead chunks, the more likely trashing will > occur. In my opinion, using more than 128 K IO chunks will not > improve performances with modern hard disks connected to a > reasonnably fast controller, but will increase memory pressure > and probably thrashing.
Your opinion seems to differ from actual measurements made by Roger Larsson and other people.
But yes, increasing the readahead window also increases the chance of readahead window thrashing. Luckily we can detect fairly easily if this is happening and use that to automatically shrink the readahead window...
regards,
Rik -- IA64: a worthy successor to the i860.
http://www.surriel.com/ http://www.conectiva.com/ http://distro.conectiva.com/
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |