Re: git blame with valgrind massif

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 




On Tue, 11 Dec 2007, Jon Smirl wrote:
> 
> How do you interpret the massif output?

Not very easy, since massif will tell you what *allocated* it, but then 
trying to see who was supposed to free it is another issue altogether.

I also find the textual output to be very confusing. But what massif is 
really good at is to look at the memory usage over time in the postscript 
file it generates, and that gives you a much better feel for what 
particular allocation is a problem.

In this case, it's patch_delta that generates all the memory usage (well, 
98% of it ;^), but that's not that helpful unless you know git internals, 
and realize that with deep delta chains, that only means that the memory 
is kept around just for random object data. The question is why that 
object data stays around and isn't free'd.

There's two answers to that:
 - the non-buggy use of the object data in the delta base cache (limited 
   by the delta_base_cache_limit, which defaults to 16MB, although you can 
   tweak it with core.deltabasecachelimit)
 - the (possibly buggy) callers that keep the data.

See my previous email with a patch to "git blame" to make it release the 
object data. That should fix it, I think.

		Linus

-
To unsubscribe from this list: send the line "unsubscribe git" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[Index of Archives]     [Linux Kernel Development]     [Gcc Help]     [IETF Annouce]     [DCCP]     [Netdev]     [Networking]     [Security]     [V4L]     [Bugtraq]     [Yosemite]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Linux SCSI]     [Fedora Users]

  Powered by Linux