lkml.org 
[lkml]   [2003]   [Sep]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: experiences beyond 4 GB RAM with 2.4.22
On Tuesday September 9, skraw@ithnet.com wrote:
> Hello,
>
> lately I upgraded my testbox from 2 to 6 GB ram and found out some oddities I
> would like to hear your opinions.
> The box ran flawlessly and performant with 2 GB - was in fact a real joy.
> After upgrading the ram and recompiling kernel 2.4.22 with support for 64 GB I
> noticed:
>
> 1) nfs clients see timeouts again, like
>
> Sep 9 03:37:35 clienta kernel: nfs: server 192.168.1.1 not responding, still
> trying
> Sep 9 03:37:35 clienta kernel: nfs: server 192.168.1.1 OK
> Sep 9 03:37:35 clienta kernel: nfs: server 192.168.1.1 not responding, still
> trying
> Sep 9 03:37:35 clienta kernel: nfs: server 192.168.1.1 OK
> Sep 9 03:41:13 clienta kernel: nfs: server 192.168.1.1 not responding, still
> trying
> Sep 9 03:41:13 clienta kernel: nfs: server 192.168.1.1 OK
>
> Both are 2.4.22. 192.168.1.1 is the testbox. I saw those with 2GB, but could
> fix it through more nfs-daemons and
>
> echo 2097152 >/proc/sys/net/core/rmem_max
> echo 2097152 >/proc/sys/net/core/wmem_max
>
> Are these values too small for 6 GB?

No. The values are proportional to the number of server threads, not
the amount of RAM... and they should be un-necessary after 2.4.20
anyway as nfsd in the kernel makes the appropriate settings.


>
> 2) Box is very slow, kswapd looks very active during tar of a local harddisk.
> Interactivity is really bad. Seems vm has a high time looking for free or
> usable pages. Compared to 2 GB the behaviour is unbelievably bad.
>
> 3) Network performance has a remarkable dropdown during above tar. In fact
> doing simple pings every few minutes shows that quite a lot of them are simply
> dropped, never make it over the ethernet.

My only guess is that it is doing a lot of copying into low memory
because your devices can only DMA into/outof low memory.
Have you tried 2.6 ??
How about CONFIG_HIGHMEM4G ?
It won't use all the RAM, but it would be interesting if it were
faster.

NeilBrown
-
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/

\
 
 \ /
  Last update: 2005-03-22 13:48    [from the cache]
©2003-2014 Jasper Spaans. hosted at Digital Ocean