On Mon, 25 Oct 2004, Eric Worthy wrote: > > Anyone have any advice on what I could be doing wrong or how to improve > the performance of the scanning?
We always get a great performance boost in software by adding -march=(yourcpuhere) -O2 -fomit-frame-pointer -static to the build lines. If you can build static binaries an additional CPU register is available for function calls (EDX iirc). If you're a quad p3 xeon, you want -march=i686. You might also play with benching -O2 vs -03. We seem to get mixed results depending on the nature of the software. Some perform worse at -O3 and except for some weirdness in loop unrolling, I'm not sure why O3 would give slower performance. Make sure that this happens for at least clam and clamd. (caveot: some optimizations can create instability so test it). Clam uses many libraries like libz and rebuilding those dependent libraries may help as well (may not matter if staticly linked?) Another point to look at is disk o/i bottle neck. Mail has a tendency to write-copy-write-copy-write especially when you have a scanner and an MTA. This creation and deletion of spool files makes for a lot of journal traffic (ext3/reiser, assuming Linux) to the hard drive. Unfortunately, journal traffic is largely synchronous so it can rollback transactions in the event of a failure. Filesystem noatime,notail options are your friend here. You can get some mileage by putting your MTA's temp dir on a shmfs/tmpvs or other type of VM filesystem if you're on a different OS to reduce the disk i/o cycles. By freeing I/O cycles, the cpus can do more *real* work and not wait precious cycles on io time. On a 2.6 kernel, vmstat will tell you io-wait time (wa) get a feel for where the bottle neck is. Hope this helps. We're constantly fighting io wait here due to the virus spam and message spool/accounting database and currently our bottleneck is definitely disk, not cpu (3.2ghz p4-ht). -- Eric Wheeler Vice President National Security Concepts, Inc. PO Box 3567 Tualatin, OR 97062 http://www.nsci.us/ Voice: (503) 293-7656 Fax: (503) 885-0770 _______________________________________________ http://lists.clamav.net/cgi-bin/mailman/listinfo/clamav-users
