When the dictionary is <= 8 bytes, no data is loaded from the dictionary.
In this case the repcodes weren't set, because they were inserted after the
size check. Fix this problem in general by first setting the cdict state to
a clean state of an empty dictionary, then filling the state from there.
Produces 3 statistics for ongoing frame compression :
- ingested
- consumed (effectively compressed)
- produced
Ingested can be larger than consumed due to buffering effect.
For the time being, this patch mostly fixes the % ratio issue,
since it computes consumed / produced,
instead of ingested / produced.
That being said, update is not "smooth",
because on a slow enough setting,
fileio spends most of its time waiting for a worker to complete its job.
This could be improved thanks to more granular flushing
i.e. start flushing before ongoing job is fully completed.
would create too large buffers,
since default job size == window size * 4.
This would crash on 32-bit systems.
Also : jobSize being a 32-bit unsigned, it cannot be >= 4 GB,
so the formula was failing for large window sizes >= 1 GB.
Fixed now : max job Size is 2 GB, whatever the window size.
this happened on 32-bits build when requiring a too large input buffer,
typically on wlog=29, creating jobs of 2 GB size.
also : zstd32 now compiles with multithread support enabled by default
(can be disabled with HAVE_THREAD=0)
Shaves 492,076 B off of the `ZSTD_CDict`.
The size of a `ZSTD_CDict` created from a 112,640 B dictionary is:
| Level | Before (B) | After (B) |
|-------|------------|-----------|
| 1 | 648,448 | 156,412 |
| 3 | 1,140,008 | 647,932 |
This new parameter makes it possible to call
streaming ZSTDMT with a single thread set
which is non blocking.
It makes it possible for the main thread to do other tasks in parallel
while the worker thread does compression.
Typically, for zstd cli, it means it can do I/O stuff.
Applied within fileio.c, this patch provides non-negligible gains during compression.
Tested on my laptop, with enwik9 (1000000000 bytes) : time zstd -f enwik9
With traditional single-thread blocking mode :
real 0m9.557s
user 0m8.861s
sys 0m0.538s
With new single-worker non blocking mode :
real 0m7.938s
user 0m8.049s
sys 0m0.514s
=> 20% faster
it still fallbacks to single-thread blocking invocation
when input is small (<1job)
or when invoking ZSTDMT_compress(), which is blocking.
Also : fixed a bug in new block-granular compression routine.
Pathological samples may result in literal section being incompressible.
This case is now detected,
and literal distribution is replaced by one that can be written into the dictionary.
constants in zstd.h should not depend on MIN() macro which existence is not guaranteed.
Added a test to check the specific constants.
The test is a bit too specific.
But I have found no way to control a more generic "are all macro already defined" condition,
especially as this is a valid construction (the missing macro might be defined later, intentionnally).
in a new "custom memory allocator" paragraph
which is itself part of "memory management" category.
This makes it simpler to see the relation between the type and its usages.
It used to stop on reaching extDict, for simplification.
As a consequence, there was a small loss of performance each time the round buffer would restart from beginning.
It's not a large difference though, just several hundreds of bytes on silesia.
This patch fixes it.
now selected for levels 13, 14 and 15.
Also : dropped the requirement for monotonic memory budget increase of compression levels,,
which was required for ZSTD_estimateCCtxSize()
in order to ensure that a memory budget for level L is large enough for any level <= L.
This condition is now ensured at run time inside ZSTD_estimateCCtxSize().
we want the dictionary table to be fully sorted,
not just lazily filled.
Dictionary loading is a bit more intensive,
but it saves cpu cycles for match search during compression.
