Messages in this thread | | | From | Neil Brown <> | Date | Fri, 12 Sep 2003 12:46:46 +1000 | Subject | Re: experiences beyond 4 GB RAM with 2.4.22 |
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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.
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