Development

About strict-aliasing optimization

What is strict aliasing? To make the long thing short, it means that the compiler apply strictest aliasing rules applicable to the language and having these assumptions the optimizer can do further optimizations.

To quote gcc manual:

Cleaning up FreeBSD userland to make them WARNS=6 clean

I have started to clean up certain code of FreeBSD userland I interest or use at company, to make them WARNS=6 clean. A patchset separated by categories would be posted on my home directory at freefall right after I have a preliminary test.

Ruslan has suggested that I should have used ``make universe’’ to test my patches and I’ll try this on some 1750 boxes - my laptop is too slow and its hard disk is too small to finish a full make universe build :-)

em(4) performance issue?

Today NetApplience folks has told me that Linux performance is twice better than FreeBSD when using em(4) driver, and they pointed out that the driver FreeBSD is using does not do a good job at this time. I have tried to tune some certain part of the kernel however the result is still not so good at the time I am writing.

失之厘豪，谬以千里

Today, JINMEI Tatuya / 神明達哉 has submitted a patch against sys/kern/uipc_socket2.c, which is:

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Index: src/sys/kern/uipc_socket2.c
diff -u src/sys/kern/uipc_socket2.c:1.138 src/sys/kern/uipc_socket2.c:1.139
--- src/sys/kern/uipc_socket2.c:1.138	Tue Oct 19 15:13:30 2004
+++ src/sys/kern/uipc_socket2.c	Wed Oct 27 05:37:58 2004
@@ -1253,7 +1253,7 @@
 
 	if (CMSG_SPACE((u_int)size) > MCLBYTES)
 		return ((struct mbuf *) NULL);
-	if (CMSG_SPACE((u_int)size > MLEN))
+	if (CMSG_SPACE((u_int)size) > MLEN)
 		m = m_getcl(M_DONTWAIT, MT_CONTROL, 0);
 	else
 		m = m_get(M_DONTWAIT, MT_CONTROL);

HP LJ1000 USB Printer wierdness

I have fighted against the issue that LJ1000 can’t work correctly with FreeBSD however I have failed.

I got “ulpt0: Input/Output Error” when doing cat foo > /dev/ulpt0.

Of course, cups and friends won’t run with this state.

This problem exists in FreeBSD 5.3-RC, 4.10-STABLE. However, interestingly Windows works correctly.

So, why??

RIP: GNU awk

Today DragonFly has buryed GNU awk. G’bye, amen! :-D

Starting to use GAIM etc under FreeBSD

In order to touch more bugs in FreeBSD so I can fix it, I have switched to FreeBSD and installed GAIM, etc. Amazingly, it seems that 5-STABLE is much more stable then I expect :D

I have installed GAIM and OpenQ (Yes, thanks for all folks who ported it, while I rarely and rarely using QQ these days), and it’s quite good!

Scott Long's em(4) super speedup patch

Scott Long have committed this which will:

Two PRs and an ongoing patch

ZHAO Xin (a colleague of mine) has pointed out that GNOME Simplified Chinese does not did a good work when displaying time. He then filed ports/72722 and ports/72723.

Adam Weinberger (adamw@, one of the major FreeBSD GNOME maintainers) has then pointed out that it might be better to contact the Simplified Chinese Translation team. In a private mail, I have explained that the root cause of the issue, however, is that our libc implementation does not implemented the GNU Extensions, say, the -_^0 extensions of strftime(3). Adam have then kindly approved that the patches should be committed, and we should have a long-run solution then finally remove them.

Investigating 5.3-RC1 panic

Before reporting this to the list, I would first gather enough information.

Alu’s server boxes is suffering in continued reboot when server is loaded. Because he is supporting FreeBSD by utilizing 5.3-RC1 in his production environment (and it’s moderately loaded as it is connected to the ChinaNet Backbone), and donated many devices for dedicated services of the FreeBSD China Community, I think we must help him to solve these out.

I have plugged a new kernel configuration on his box in order to obtain a (potential) crashdump and figure out what is happening. Maybe we will get it tomorrow.

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