Chip Salzenberg wrote:
>
> While running the "brutal" (-- Alan Cox) Cerberus test suite on a
> 2.2.17pre10 kernel, we've been seeing pauses of from five to twenty
> seconds every two minutes or so. As best I can tell from SysReq, when
> the kernel pauses, it's spending time in shrink_mmap(). When pauses
> occur, free RAM is down to about 1M; but it's not a true OOM, since
> there's always lots of free swap space. (Cerberus scales its memory
> usage to avoid filling swap.)
>
> Good News: The pauses are *almost* completely gone after applying
> Andrea's patch entitled "VM-global-patch-1". The kernel still pauses,
> but only very occasionally, and for no more than two to four seconds;
> and even during the pauses, interactive performance is reasonable.
> According to Jason Collins, creator of Cerberus, it's at least as good
> as any previous 2.2.x when subjected to a Cerberus attack.
>
> Thanks, Andrea!
>
> PS: Anyone who wants to stress the VM, I recommend trying Cerberus
> as part of your testing mix. Get it from SourceForge:
> <URL:https://sourceforge.net/projects/va-ctcs/>
>
> Testing Details:
> Kernel: 2.2.17pre10
> Config: SMP, 2G, NFS root
> Hardware: Intel Lancewood, two P3s, 512M RAM, DAC960 RAID
> Relevant Patches:
> Dave/Trond/Neil's NFS merge
> Andrea's VM-global-patch-1
> Andrea's BIGMEM
> Solar Designer's security
> Probably Irrelevant Patches:
> Rik's fair share scheduler (but disabled at the time)
> Andre Hedrick's IDE
> Mingo's RAID
> VA's E820 memory probe
> Backport of 2.4's AGP driver
>
My experience is totally opposite. I'm running a production
mail server with sendmail and cyrus and have tested about every
kernel from 2.2 tree but they all pause for tens of seconds,
when load is higher more often making sometimes machine unusable.
The 2.2.17pre9 + Andrea's VM-global-patch-1 makes no difference
for this setup.
Also running: Mingo's RAID, SMP
Regards,
ds
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This archive was generated by hypermail 2b29 : Sat Jul 15 2000 - 21:00:08 EST