[cvsnt] Stress Tests results for CVSNT/CVS/Subversion

[Trevor Leybourne]

We've noticied similar things whereby CVSNT will just take for ever to
do a simple Update or Checkout. Where a Checkout normally takes 1-2
minutes for a module, doing a Update suddenly will take 30-60 minutes
for the same module. I've found no way to easily reproduce (so haven't
reported it as a issue), but it has been happening about 1 or 2 times a
week, over the last couple of months. Normally we either reboot the
server or eventually CVSNT comes back to normal. 

We're running 2.5.01 as our server and clients are all 2.5.01 or higher
as well. 

I'm waiting for the next suite release to see if it solves the problem. 

Trevor

> -----Original Message-----
> From: cvsnt-bounces at cvsnt.org 
> [mailto:cvsnt-bounces at cvsnt.org] On Behalf Of Arthur Barrett
> Sent: Thursday, 9 February 2006 10:35 a.m.
> To: Rahul Bhargava; cvsnt at cvsnt.org
> Subject: RE: [cvsnt] Stress Tests results for CVSNT/CVS/Subversion
> 
> Rahul,
> 
> We would prefer it if you consulted for advice before running 
> such tests rather than after.
> 
> If you still have the test set available we would appreciate 
> being able to diagnose the cause of the cvslockd hang.
> 
> Knowing which build of CVSNT 2.5.03 you used would also be of 
> assistance.
> 
> Regards,
> 
> 
> Arthur Barrett
> 
> 
> -----Original Message-----
> From:	cvsnt-bounces at cvsnt.org on behalf of Rahul Bhargava
> Sent:	Thu 2/9/2006 6:44 AM
> To:	cvsnt at cvsnt.org
> Cc:	
> Subject:	[cvsnt] Stress Tests results for CVSNT/CVS/Subversion
> 
> FYI,
> 
> Just wanted to share some stress test results with the CVSNT 
> community.
> 
> We recently undertook an extensive stress test exercise with 
> the objective of understanding how CVSNT, CVS, Subversion 
> servers behave under high client load.
> 
> We created a bank of client machines  (Windows 2k3, Linux 
> 2.6.x) to generate client load. The workload that each client 
> iterated through was the usual cvs/cvsnt/subversion command 
> set that a development organization would see - import, 
> update, checkout, log , diff, tag, rtag, status etc Each 
> client would repeatedly execute the same workload with or 
> without a wait time.
> 
> With 50 clients pounding on a CVSNT server (2.5.03) running 
> on a Windows
> 2003 Server machine
> with 1GB RAM, 2GB SWAP, 2xPentium 4 CPUs (2.8GHz Dell server 
> class machine), we saw that after about 15 minutes of stress 
> the CVSNT Lock Daemon service would freeze, the CPUs would be 
> maxed out at 100%. When the freeze happened, almost always 
> the command `rtag' would be the one running. We would see 
> several clients trying to `rtag' the same module leading up 
> to the freeze. Sometimes add/commit would trigger similar 
> issue. The clients were running the same CVSNT version also 
> (2.5.03). Shutting down the lock daemon service immediately 
> brought the CPUs back to idling state.
> 
> We tried the same stress run on a Linux 2.6.5, 2 CPU machine. 
> The clients were running on Win/Linux and the CVSNT 2.5.03 
> server was running on the Linux box. Similar results - the 
> server would go on for
> 15 mins - 2 hours before hanging the Linux machine. The CPUs 
> would be maxed out and the only way out would be to reboot 
> the Linux box.
> 
> Next we tried the same experiment with CVS (1.11.21) and we 
> could run the stress for days without any issue.
> The CPU usage would be fairly low with and we didn't see any 
> freezes or hangs.
> 
> Similar experience with the latest Subversion release (1.3.0) 
> - we could run the stress for days without any problems. The 
> CPU consumption was a lot higher than vanilla CVS. Subversion 
> `svnserve' processes would consume around 80% of the CPUs 
> when the stress was on. Other than that, checkouts were 
> noticeably slower with subversion as the number of revisions grew.
> 
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