kernel rebuild using mk_kernel with ANSI C

[Pete Des Moulins]

When I build a new kernel on an rp7410 with HP-UX 11i the size is approx. 26MB. After installation of ANSI C the rebuilt kernel is only 18MB. Will the new kernel work as efficiently as the larger one and why is there such a size difference.
Surely it would be better if kernel rebuilds always used the HP C compiler for consistency.

[Massimo Bianchi]

Hi,
are you sure you didn't change any parameter in the kernel ?

Usually the kernel rebuild uses the internal C compiler, AFAIK, and the installation should have not changed anything.

Try comparing /stand/system and /stand/system.prev, is there any difference (assuming just one kernel rebuild)?

HTH,
Massimo

[Stefan Farrelly]

Installing ANSI-C on 11i doesnt require a reboot. The software does not have the is_reboot flag set, so why did you have a new kernel rebuilt ?

something else you installed required the reboot and its changed the kernel. Depending on what changed the size of the kernel can change dramatically, as in your case. You need to find out why/what rebuilt your kernel.

[Ravi_8]

Hi Pete

are you looking at /stand/vmunix or /stand/build/vmunix_test,

while building new kernel(mk_kernel)/stand/build/vmunix_test will be generated which will replace(move to) /stand/vmunix.
as long as kernel is building up without any problem and system is coming up with new kernel size of the file doesn't matter.

[Pete Des Moulins]

Without ANSI C installed using mk_kernel produces a /stand/build/vmunix_test of 26MB. After installing ANSI C and without any other changes, using mk_kernel produces a /stand/build/vmunix_test of 18MB. Using the "what" command on both versions of vmunix_test produces identical results. My real concern is that the smaller version of vmunix will be slower than the previous version. Has anyone any experience of this?

[Stefan Farrelly]

Yes, we have experienced this also on some of our servers. For example, 2 identically built 11i servers (only difference is one has HP ANSI C installed) and vmunix is 17MB on the server with ANSI, and 26MB on the server without. We were worried by this also, but after checking it seems to be absolutely fine. Weve never had any problems on any our servers liek this.
All I can think is that ANSI-C implements newer libraries optimized for PA-RISC which thus reduces the kernel build size, and this is a positive bonus!