Hi,
Lasse Collin wrote:
> With compression, -T0 in 5.1.1alpha sets the number of threads to match
> the number of CPU cores. If no memory usage limit has been set, it may
> end up using more memory than there is RAM. Pushing the system to swap
> with threading is silly, because the point of threading in xz is to
> make it faster. So it might make sense to have some kind of default
> soft limit that is used to limit the number of threads when automatic
> number of threads is requested.
How about something like this patch, to start? With it applied, I am
happy using
XZ_DEFAULTS='--no-adjust --threads=0 --memlimit=1080MiB
(As the FIXME comment in coder_set_compression_settings() explains, it
is a little silly to waste so much space bookkeeping in those cases
where memory constraints are tight enough to only allow using one
thread, but that's a story for another day.)
---
src/xz/coder.c | 12 ++++++------
1 files changed, 6 insertions(+), 6 deletions(-)
diff --git a/src/xz/coder.c b/src/xz/coder.c
index 41193a7..5382689 100644
--- a/src/xz/coder.c
+++ b/src/xz/coder.c
@@ -229,12 +229,6 @@ coder_set_compression_settings(void)
if (memory_usage <= memory_limit)
return;
- // If --no-auto-adjust was used or we didn't find LZMA1 or
- // LZMA2 as the last filter, give an error immediately.
- // --format=raw implies --no-auto-adjust.
- if (!opt_auto_adjust || opt_format == FORMAT_RAW)
- memlimit_too_small(memory_usage);
-
assert(opt_mode == MODE_COMPRESS);
#ifdef HAVE_PTHREAD
@@ -269,6 +263,12 @@ coder_set_compression_settings(void)
if (memory_usage <= memory_limit)
return;
+ // If --no-auto-adjust was used or we didn't find LZMA1 or
+ // LZMA2 as the last filter, give an error immediately.
+ // --format=raw implies --no-auto-adjust.
+ if (!opt_auto_adjust || opt_format == FORMAT_RAW)
+ memlimit_too_small(memory_usage);
+
// Look for the last filter if it is LZMA2 or LZMA1, so we can make
// it use less RAM. With other filters we don't know what to do.
size_t i = 0;
--
1.7.8.rc3
