High CPU usage when recording from HDHomeRun?

[Boolah]

I've got an, admittedly, old machine running SageTV (software and specs below) that's been working great for more than three years. I recently got myself a second HDHomeRun (total of four tuners) and noticed a rather serious issue that I hope you guys can help me resolve.

The machine I use for SageTV is totally dedicated to SageTV - there is nothing on there except what's listed below (not even any anti-virus software). The machine does not play back any content and runs SageTV in service mode only (no GUI). I use a HD100 to play back all content.

When recording from any of the PVR cards, my CPU never goes above 5% usage, even if I have all 4 tuners recording simultaneously. However, when recording a single stream from the HDHomeRun (with no other recording running and no playback), my CPU goes up to 40%. If I record a second stream my CPU goes up to 80%. If I record a third stream, my system can't keep up, the CPU pegs at 100% and I start dropping frames.

At first I thought my hard drives or network was the bottleneck, but I can record four simultaneous HD streams from the HDHomeRun outside of SageTV, through the HDHomeRun software directly. Moreover, the machine can do this without going above 20% CPU usage. To accomplish this, I open up a DOS box and enter the following four times, with different HDHR IDs, channels/programs and tuners:

hdhomerun_config.exe <HDHR ID> set /tuner0/channel qam256:100
hdhomerun_config.exe <HDHR ID> set /tuner0/program 1
hdhomerun_config.exe <HDHR ID> save /tuner0 SavedFile.mpg

Executing the above provides the additional benefit of showing any network congestion/packet loss which might occur, none of which I found.

Does anyone have any idea why SageTV should be using so much CPU when recording from the HDHomeRun?

Hardware:
Intel Celeron 2.8GHz
ATI Radeon 9600
1 GB PC-3200 RAM
1 Gbit Intel NIC (connected to a gigabit switch)
2.5TB (total) local storage (no remote storage is used for SageTV)
Hauppauge WinTV PVR-250 (three cards)
Hauppauge WinTV PVR-150 (one card)
HDHomeRun (two devices, total of four tuners)
USB-UIRT

Software:
Windows XP Pro SP3
SageTV v6.5.9
Java JRE v6.0u11
HDHomeRun v20090215
USB-UIRT Drivers v1.4
Adobe Acrobat Reader v8.1.3
WinVNC v1.0.5.3
Belkin Bulldog Plus v4.0.2.1219 (UPS shutdown software)

[thatdude90210]

My software firewall used to do that. I was using Kerio 4.12 or something and my system was using up 25% cpu (x2 5400) just recording from HDhomerun. I switch to XP's build in firewall and it went to 0-5%. I'm currently trying out comodo firewall, seems ok so far too.

[Boolah]

There's no software firewall on the machine at all. Even Windows XP's built-in firewall has been disabled.

[gplasky]

Double check and make sure the Sage version you are running on the server is the latest. There was this problem with a previous version which was fixed in the latest release.

Gerry

[Boolah]

Yes, it's the latest official release (v6.5.9.204).

I believe the problem with earlier releases was that Sage would not isolate the specific program from the full channel stream with the HDHomeRun. I can see this is not happening since tuning a single 1080i program through SageTV, it only generates ~16 Mbps of traffic.

[robogeek]

Is it specifically the SageTV process that is at high CPU usage, or is it the System process that is at high CPU usage? If it's the SageTV process, try enabling the debug log and submit a bug report to SageTV. If it's the System process it's probably your network adapter driver or adapter settings. I had a gigabit ethernet adapter that would cause the System process jump to noticably higher CPU usage when running ShowAnalyzer to process multiple recordings over the network.

[Boolah]

The CPU usage seems pretty evenly split between the SageTVService.exe process and the System process. Upgrading the NIC drivers didn't help either. However, if it were a problem with the NIC drivers, I would think that I should be seeing the same issue irrespective of whether I'm recording through SageTV or through the HDHomeRun tool.

When recording with the HDHomeRun software, the System process fluctuates between 0% and 2% while the hdhomerun_config.exe process fluctuates between 0% and 8%, a remarkable difference when recording through SageTV.

Thanks for all the suggestions. I guess it's time to enable debug logging and contact SageTV.

[betafish]

I think I have a similar problem but I am not using HDHomerun. I have the server and client on the same machine and I am using an AverTVHD A180 card. On one OTA channel the CPU maxes out at 100%. Sage is the application process running at 99% when I switch to the particular channel which broadcasts in HD. Other HD channels have no problem but I can easily reproduce the problem by switching to that channel.