[Top][All Lists]

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

Re: [Libunwind-devel] non-local return scalability bottleneck

From: Milian Wolff
Subject: Re: [Libunwind-devel] non-local return scalability bottleneck
Date: Mon, 07 Dec 2015 21:49:43 +0100
User-agent: KMail/5.1.42 pre (Linux/4.2.5-1-ARCH; KDE/5.16.0; x86_64; ; )

On Sonntag, 6. Dezember 2015 11:31:17 CET Paul Pluzhnikov wrote:
> On Sun, Dec 6, 2015 at 11:03 AM, Arun Sharma <address@hidden> wrote:
> > Suspect the comment below is relevant. Perhaps try removing it and see
> > what happens?
> I suspect that the dlclose resulting in unload, followed by dlopen of
> something else that lands in the same address range,  is what would
> break (by returning now stale info).

I've seen this bottleneck myself btw. in my heaptrack profiler - it costs both 
pure CPU performance as well as severely impacting the multi-thread 

I was thinking of writing a patch for an off-by-default cache with the 
capability to manually invalidate the cache whenever dlopen/dlcose gets called 
(which is rare, and detectable by a profiler). I never got around to write it 
though... If anyone could do that - it would be much appreciated!

That said, I did write this patch which is still not reviewed or accepted 

@Luke: Could you try that patch and increase the cache size? That should 
already reduce the number of times dl_iterate_phdr gets called.

@Arun: Any chance you could review and land it?

Milian Wolff

Attachment: signature.asc
Description: This is a digitally signed message part.

reply via email to

[Prev in Thread] Current Thread [Next in Thread]