This is the mail archive of the mailing list for the glibc project.

Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: [PATCH] [RFC] malloc: Reduce worst-case behaviour with madvise and refault overhead

On Wed, Feb 11, 2015 at 01:34:53PM +0000, Mel Gorman wrote:
> > This indicates to me that the problem might actually be significant
> > over-allocation beyond the size that's actually going to be used. Do
> > we have some real-world specific examples of where this is happening?
> In the case of ebizzy, it is the case that do_stuff is so small that the
> allocation/free cost dominates.

ebizzy is supposed to be a benchmark simulating typical workload,
right? If so, I think this specific test operation is a mistake, and I
think glibc should be cautious about optimizing for benchmarks that
don't reflect meaningful real-world usage.

> In the cases where I've seen this happen
> on other workloads (firefix, evolution, mariadb during database init from
> system) the cost of the operations on the buffer dominated. The malloc/free
> cost was there but the performance difference is in the noise.

If it's not distinguishable from noise in actual usage cases, then I'm
skeptical that there's a need to fix this issue.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]