Re: [PATCH] git-rev-list: give better diagnostic for failed write

On Tue, 26 Jun 2007, Theodore Tso wrote:

On Tue, Jun 26, 2007 at 10:32:23AM -0700, Linus Torvalds wrote:

quoted

But we actually _do_ want fully buffered from a performance angle. 
Especially for the big stuff, which is usually the *diffs*, not the commit 
messages. Not so much an issue with git-rev-list, but with "git log -p" 
you would normally not want it line-buffered, and it's actually much nicer 
to let it be fully buffered and then do a flush at the end.

Well, sometimes we do and sometimes we don't right?

No.

We basically _never_ want "line buffered" or "unbuffered", which is what 
stdio knows how to do. That sucks in _all_ cases.

What we want is "fully buffered" for plain files, and "record buffered" 
for anything else (where a "record" is basically the "commit + optional 
diff").

We can get the record buffered by adding the fflush() calls, but the thing 
is, we'd want to _avoid_ that if it was a file. It's just that there is no 
way to set that kind of flag portably with stdio, we'd have to carry it 
around _separately_ from stdio, which is a big pain.

But if we decide that this only matters with stdout (which currently is 
what the patches have done), we could of course just make it a single 
global variable (like "stdout" itself already is). Then we could just make 
git.c start out by testing stdout at startup and setting the global 
variable.

		Linus