similar to: RFC: Improving performance of HashString

According to... https://github.com/rurban/smhasher/blob/master/README.md Bernstein has quality problems (while xx is as good as you get in a non-crypto hash), and xx is 7x (32 bit) - 12x (64 bit) faster. That's on long strings. It would be worth checking the startup overhead for typically short identifiers in programs. See later on in the README: "When used in a hash table the

On Tue, Apr 25, 2017 at 12:55 PM, Vedant Kumar via llvm-dev <llvm-dev at lists.llvm.org> wrote: > >> On Apr 24, 2017, at 5:37 PM, Scott Smith via llvm-dev <llvm-dev at lists.llvm.org> wrote: >> >> I've been working on improving the startup performance of lldb, and ran into an issue with llvm::HashString. It works a character at a time, which creates a long

On Tue, Feb 14, 2012 at 2:44 AM, Chris Lattner <clattner at apple.com> wrote: > On Feb 13, 2012, at 2:00 AM, Talin wrote: > > Just out of curiosity, why not MurmurHash3 ? This page seems to >> suggest that #2 has some flaw, and #3 is better all round: >> >> https://sites.google.com/site/murmurhash/ >> >> The main reason is because there's no

On Mon, Feb 13, 2012 at 1:22 AM, Jay Foad <jay.foad at gmail.com> wrote: > On 13 February 2012 00:59, Talin <viridia at gmail.com> wrote: > > Here's my latest version of Hashing.h, which I propose to add to > llvm/ADT. > > Comments welcome and encouraged. > > > /// Adapted from MurmurHash2 by Austin Appleby > > Just out of curiosity, why not

On Feb 13, 2012, at 2:00 AM, Talin wrote: > Just out of curiosity, why not MurmurHash3 ? This page seems to > suggest that #2 has some flaw, and #3 is better all round: > > https://sites.google.com/site/murmurhash/ > > The main reason is because there's no incremental version of 3. I think that that is a great reason. > LLVM's needs, on the other hand, are fairly

On Mon, Mar 16, 2015 at 11:00 PM, David Blaikie <dblaikie at gmail.com> wrote: > > > On Mon, Mar 16, 2015 at 10:52 PM, Davide Italiano <davide at freebsd.org> > wrote: >> >> On Mon, Mar 16, 2015 at 1:54 AM, Davide Italiano <davide at freebsd.org> >> wrote: >> > >> > Shankar's parallel for per-se didn't introduce any

On Feb 14, 2012, at 10:47 PM, Talin wrote: > /// Add a pointer value > template<typename T> > void add(const T *PtrVal) { > addImpl( > reinterpret_cast<const uint32_t *>(&PtrVal), > reinterpret_cast<const uint32_t *>(&PtrVal + 1)); > } > > This violates TBAA rules and looks pretty dangerous to expose as public API.

(Again), while trying to improve the performance of lldb, I ran into a bottleneck with the demangler. This may be specific to my platform - Ubuntu 16.04, probably using libstdc++, not libc++. It makes extensive use of std::string and std::vector, and I see memory allocation at the top. I prototyped a version that uses an arena-style memory allocator (you can allocate, but you can't ever

On Tue, Feb 14, 2012 at 2:44 AM, Chris Lattner <clattner at apple.com> wrote: > On Feb 13, 2012, at 2:00 AM, Talin wrote: >> >> Just out of curiosity, why not MurmurHash3 ? This page seems to >> suggest that #2 has some flaw, and #3 is better all round: >> >> https://sites.google.com/site/murmurhash/ >> > The main reason is because there's no

well, top-of-branch lldb uses this code, that's how I found it. Do you mean libc++'s demangler? FYI when I said 14+% (and now it's 17%), I mean the overall performance of starting lldb, not just the demangler itself. It's probably several times faster now with this change (https://reviews.llvm.org/D32500) On Tue, Apr 25, 2017 at 12:19 PM, Vedant Kumar <vsk at apple.com>

Back in the spring, we started using rsync for a disk to disk backup system maintaining close to 10PB of data. I am not here to debate the issue of what is the right tool but only to discuss what we found to be a problem with rsync when doing so. We traced the various processes hoping to find what the culprit was slowing things down so much and determined pretty easily that it was the

On Tue, Apr 25, 2017 at 8:36 PM, Vedant Kumar via llvm-dev < llvm-dev at lists.llvm.org> wrote: > > > On Apr 25, 2017, at 12:24 PM, Scott Smith <scott.smith at purestorage.com> > wrote: > > > > well, top-of-branch lldb uses this code, that's how I found it. Do you > mean libc++'s demangler? > > Thanks for explaining, this is the first time

I don't disagree that MD5 could (or even should) be replaced so it is no longer the bottleneck in several real-world cases (including mine). However this patch is not for MD5 performance, rather for the rolling checksum rsync uses to match blocks on existing files on both ends to reduce transfer size. On Mon, May 18, 2020 at 5:44 PM Filipe Maia via rsync <rsync at lists.samba.org>

On Tue, Apr 25, 2017 at 1:37 PM, Asiri Rathnayake < asiri.rathnayake at gmail.com> wrote: > > > On Tue, Apr 25, 2017 at 8:36 PM, Vedant Kumar via llvm-dev < > llvm-dev at lists.llvm.org> wrote: > >> >> > On Apr 25, 2017, at 12:24 PM, Scott Smith <scott.smith at purestorage.com> >> wrote: >> > >> > well, top-of-branch lldb

How do you compile LLD? There's a big difference between when using MSVC vs Clang. The parallel ghash patch I was mentioning is almost 2x as fast when using Clang 7.0+ vs. MSVC 15.9+, I don't know exactly why. I also suggest you use the Release target. You should also grab this patch: https://reviews.llvm.org/D55056 - I had to revert it because it was causing issues with LLDB. But it

On Tue, Jun 26, 2018 at 1:28 PM Adrian Prantl <aprantl at apple.com> wrote: > > > > On Jun 26, 2018, at 11:58 AM, Zachary Turner via llvm-dev < > llvm-dev at lists.llvm.org> wrote: > > > > Hi all, > > > > We have been thinking internally about a lightweight llvm-based > ptracer. To address one question up front: the primary way in which this

On Tue, Jul 6, 2010 at 9:08 AM, Greg Clayton <gclayton at apple.com> wrote: >> 2) Can I easily debug JIT'd code with LLDB? > > Are you running JIT'd code within another process that can be debugged (i.e. the simulation binary)? If so, you might want to have LLVM generate a full blown dylib, not just a JIT'd chunk of code and load the dylib using the standard shared

Wouldn't it mean each time a function is compiled it would need to be bundled to its own dylib? How well would that scale? Félix Le 2010-07-07 à 15:41:18, Reid Kleckner a écrit : > On Tue, Jul 6, 2010 at 9:08 AM, Greg Clayton <gclayton at apple.com> wrote: >>> 2) Can I easily debug JIT'd code with LLDB? >> >> Are you running JIT'd code within another

Times for lld compiled with LTO: Input File Reading: 1430 ms ( 3.3%) Code Layout: 486 ms ( 1.1%) PDB Emission (Cumulative): 41042 ms ( 94.6%) Add Objects: 33117 ms ( 76.4%) Type Merging: 25861 ms ( 59.6%) Symbol Merging: 7011 ms ( 16.2%) TPI Stream Layout: 996 ms ( 2.3%) Globals Stream Layout:

Sadly the patch on https://reviews.llvm.org/D55585 didn't apply on my clone of llvm at all :( It will take me quite some time to test this out. On Mon, Feb 25, 2019 at 5:08 PM Alexandre Ganea <alexandre.ganea at ubisoft.com> wrote: > > For enabling large memory pages, see this link: https://support.sisoftware.co.uk/knowledgebase.php?article=52 > > Meow hash isn't in the