Displaying 7 results from an estimated 7 matches for "getva".
2017 Feb 28
4
[lld] We call SymbolBody::getVA redundantly a lot...
tl;dr: it looks like we call SymbolBody::getVA about 5x more times than we
need to
Should we cache it or something? (careful with threads).
Here is a link to a PDF of my Mathematica notebook which has all the
details of my investigation:
https://drive.google.com/open?id=0B8v10qJ6EXRxVDQ3YnZtUlFtZ1k
There seem to be two main regimes that w...
2017 Mar 01
2
[lld] We call SymbolBody::getVA redundantly a lot...
On Tue, Feb 28, 2017 at 12:10 PM, Rui Ueyama <ruiu at google.com> wrote:
> I don't think getVA is particularly expensive, and if it is not expensive
> I wouldn't cache its result. Did you experiment to cache getVA results? I
> think you can do that fairly easily by adding a std::atomic_uint64_t to
> SymbolBody and use it as a cache for getVA.
>
You're right, caching it...
2017 Mar 01
2
[lld] We call SymbolBody::getVA redundantly a lot...
...on shouldn't cost too
much)
-- Sean Silva
>
> On Tue, Feb 28, 2017 at 11:15 PM, Sean Silva <chisophugis at gmail.com>
> wrote:
>
>>
>>
>> On Tue, Feb 28, 2017 at 12:10 PM, Rui Ueyama <ruiu at google.com> wrote:
>>
>>> I don't think getVA is particularly expensive, and if it is not
>>> expensive I wouldn't cache its result. Did you experiment to cache getVA
>>> results? I think you can do that fairly easily by adding a
>>> std::atomic_uint64_t to SymbolBody and use it as a cache for getVA.
>>>...
2016 Mar 16
2
LLD performance w.r.t. local symbols (and --build-id)
...g/svn/llvm-project/lld/trunk at 263222
91177308-0d34-0410-b5e6-96231b3b80d8
r263225 ~4% speedup for ScyllaDB
commit 34ca5194d5e5e28d760cc8a730a2e1f3b2b6a21f
Author: Rafael Espindola <rafael.espindola at gmail.com>
Date: Fri Mar 11 12:19:05 2016 +0000
Compute value of local symbol with getVA.
git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk at 263225
91177308-0d34-0410-b5e6-96231b3b80d8
r263227 ~2-3% slowdown for ScyllaDB
commit 6b96b614d9e0232b106165255148af8909607ec1
Author: George Rimar <grimar at accesssoftek.com>
Date: Fri Mar 11 12:57:52 2016 +0000
[ELF]...
2016 Nov 27
3
A couple metrics of LLD/ELF's performance
...t big intel cores), it
won't contend with other cores for the L3 cache. So misses here are where
cores start to feel each other's presence.
https://reviews.llvm.org/P7943
--event=LLC-load-misses
These are misses in last level cache (LLC). I.e. times that we have to go
to DRAM (SLOOOW).
The getVA codepath show up strongly and we see the memcpy into the output.
We may want to consider a nontemporal memcpy to at least avoid polluting
the cache.
These misses contend on the DRAM bus (although currently it may be
underutilized and so adding more parallelism will help to keep it busy, but
only up...
2016 Mar 16
2
LLD performance w.r.t. local symbols (and --build-id)
...308-0d34-0410-b5e6-96231b3b80d8
r263225 ~4% speedup for ScyllaDB
commit 34ca5194d5e5e28d760cc8a730a2e1f3b2b6a21f
Author: Rafael Espindola <rafael.espindola at gmail.com<mailto:rafael.espindola at gmail.com>>
Date: Fri Mar 11 12:19:05 2016 +0000
Compute value of local symbol with getVA.
git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk at 263225 91177308-0d34-0410-b5e6-96231b3b80d8
r263227 ~2-3% slowdown for ScyllaDB
commit 6b96b614d9e0232b106165255148af8909607ec1
Author: George Rimar <grimar at accesssoftek.com<mailto:grimar at accesssoftek.com>>
Date:...
2017 Sep 14
4
Do I need to modify the AddrLoc of LLD for ARC target?
...; DEBUG: arc-ld: R_ARC_S25W_PCREL relocation: 1 S: 4 A: 0 P: 0 = (vma: 0 +
> output_offset: 0 + reloc_offset: 0 - 0) & ~0x3
> DEBUG: arc-ld: type: R_ARC_S25W_PCREL insn: 2054
>
> $ ld.lld -o basic-arc-lld basic-arc.o $ARC_LINKER_LIB -Ttext=0
>
> DEBUG: lld: R_ARC_S25W_PCREL TargetVA: 4 A: 0 P: 0 <-- same P as arc-ld
> DEBUG: lld: R_ARC_S25W_PCREL: Insn: 2050 Rel: 1
> DEBUG: lld: R_ARC_S25W_PCREL: Insn: 2054 <-- same relocation value as arc-ld
>
> But with several different high address *not* 0x0, such as 0x6:
>
> DEBUG: arc-ld: R_ARC_S25W_PCREL relocati...