Hi,
I have spent about an hour diagnosing the following: I have a passwd file, about 50,000 lines in length. I had a problem with a script grepping something from it, and when debugging I found out that: Pentium4 Xeon, RedHat 9, latest RH kernel, fully updated system: time grep : passwdfile > /dev/null ~1 minute, 12 seconds Pentium4 Xeon, RedHat 7.2, latest RH kernel, fully updated system: time grep : passwdfile > /dev/null ~0.04 seconds Pentium3, RedHat 9, latest RH kernel, fully updated system: time grep : passwdfile > /dev/null ~0.08 seconds However, using `pcregrep' on the same systems yielded: Pentium4 Xeon, RedHat 9, latest RH kernel, fully updated system: time pcregrep : passwdfile > /dev/null ~0.05 seconds Pentium4 Xeon, RedHat 7.2, latest RH kernel, fully updated system: time grep : passwdfile > /dev/null ~0.08 seconds Pentium3, RedHat 9, latest RH kernel, fully updated system: time grep : passwdfile > /dev/null ~0.12 seconds As you can see, there is a HUGE discrepancy between all the results above and the Pentium4 Xeon, RedHat 9 `grep' case, about 900 times slower. I tried recompiling the .src.rpm of the RedHat 9 grep locally on the Xeon, but it yielded the same result. As such, this appears (to me) to be some kind of a grep problem when coupled with 2 Gigabytes of RAM, Xeon P4 CPU (with the HT on) on RedHat 9. While I am researching some more on this, does any of you have any idea ? My hunch is towards write(), since I also tested it with grep --mmap (which uses mmap() instead of read() for reading) and it yielded the same results. --Ariel -- Ariel Biener e-mail: [EMAIL PROTECTED] PGP(6.5.8) public key http://www.tau.ac.il/~ariel/pgp.html ================================================================= To unsubscribe, send mail to [EMAIL PROTECTED] with the word "unsubscribe" in the message body, e.g., run the command echo unsubscribe | mail [EMAIL PROTECTED]
