I think in order to do this comparison, other conditions should be equal. Comparing helper with 1 dependent load in gc_cc and helper with 2 dependent loads in gc_v5 makes no sense to me. -- Ivan
On 12/5/06, Xiao-Feng Li <[EMAIL PROTECTED]> wrote:
On 12/5/06, Mikhail Fursov <[EMAIL PROTECTED]> wrote: > Yes, now it's ok. As you see you need one extra memory load in comparison > with GC_CC helper's version. Now I'm interested if it will or won't have a > performance affect on microtests or specs. I sometimes prefer readability and modularity to some marginal performance improvement. Yes, let's see the performance impact of the extra load. :) ( I guess it should have no problem since "free" and "ceiling" stay together so one load will ensure the other one in cache. ) Thanks, xiaofeng > On 12/5/06, Xiao-Feng Li <[EMAIL PROTECTED]> wrote: > > > > On 12/4/06, Mikhail Fursov <[EMAIL PROTECTED]> wrote: > > > On 12/3/06, Xiao-Feng Li <[EMAIL PROTECTED]> wrote: > > > > > > > > Hi, patch for GCv5 alloc inlining was submitted. This patch has also > > > > some other improvement in parallel collection. > > > > > > > > Dear committer, please help to commit it at your early convenience. > > > > > > > > Mikhail, after the patch is committed, would you please have a look if > > > > the inlining can work well with GCv5 allocation? Thanks. > > > > > > > > I don't use two TLS values for the fast path allocation; instead, only > > > > one TLS value is used for GC, and it is a pointer to the GC thread > > > > local infomation. The code is the same logic as gc_alloc_fast( ) in > > > > file gc_gen/thread/mutator_alloc.cpp and gc_thread.h. (Except that the > > > > Java code has no large object threshold check, that is only one > > > > constant comparison anyway.) > > > > > > > > > > Xiao-Feng, > > > I checked the helper's part of the diff. > > > I have a question about TLS usage in your code. > > > > > > You said that you use only one TLS slot to keep the pointer to > > > GC_thread_info. > > > In this case Java code of the helper is incorrect: > > > > > > Address TLS_BASE = VMHelper.getTlsBaseAddress(); > > > > > Oh, my mistake. I should modify the statement below: > > > > > Address allocator = TLS_BASE.plus(TLS_GC_OFFSET); > > > > to be: > > Address allocator_addr = TLS_BASE.plus(TLS_GC_OFFSET); > > Address allocator = allocator_addr.loadAddress(); > > > > Right? I will submit another patch. Thanks for pointing it out. :-) > > > > Thanks, > > xiaofeng > > > > > > > Address free_addr = allocator.plus(0); > > > Address free = free_addr.loadAddress(); > > > > > > I can fix it by myself after your patch is applied, of you can resubmit > > the > > > patch.
