Add option for queue size

common.c

@@ -1,6 +1,7 @@
 #include "pixz.h"
 
 #include <stdarg.h>
+#include <math.h>
 
 
 #pragma mark UTILS
@@ -418,6 +419,7 @@ queue_t *gPipelineStartQ = NULL,
     *gPipelineMergeQ = NULL;
 
 size_t gPipelineProcessMax = 0;
+size_t gPipelineQSize = 0;
 
 pipeline_data_free_t gPLFreer = NULL;
 pipeline_split_t gPLSplit = NULL;
@@ -457,7 +459,13 @@ void pipeline_create(
 		gPLProcessCount = gPipelineProcessMax;
 	
     gPLProcessThreads = malloc(gPLProcessCount * sizeof(pthread_t));
-    for (size_t i = 0; i < (int)(gPLProcessCount * 2 + 3); ++i) {
+    int qsize = gPipelineQSize ? gPipelineQSize
+        : ceil(gPLProcessCount * 1.3 + 1);
+    if (qsize < gPLProcessCount) {
+        fprintf(stderr, "Warning: queue size is less than thread count, "
+            "performance will suffer!\n");
+    }
+    for (size_t i = 0; i < qsize; ++i) {
         // create blocks, including a margin of error
         pipeline_item_t *item = malloc(sizeof(pipeline_item_t));
         item->data = create();

pixz.c

@@ -60,7 +60,7 @@ int main(int argc, char **argv) {
 	char *optend;
 	long optint;
     double optdbl;
-    while ((ch = getopt(argc, argv, "dxli:o:tvhp:0123456789f:")) != -1) {
+    while ((ch = getopt(argc, argv, "dxli:o:tvhp:0123456789f:q:")) != -1) {
         switch (ch) {
             case 'd': op = OP_READ; break;
             case 'x': op = OP_EXTRACT; break;
@@ -81,6 +81,12 @@ int main(int argc, char **argv) {
 					usage("Need a non-negative integer argument to -p");
 				gPipelineProcessMax = optint;
 				break;
+            case 'q':
+    			optint = strtol(optarg, &optend, 10);
+    			if (optint <= 0 || *optend)
+    				usage("Need a positive integer argument to -q");
+    			gPipelineQSize = optint;
+    			break;
             default:
                 if (ch >= '0' && ch <= '9') {
                     level = ch - '0';
@@ -91,7 +97,7 @@ int main(int argc, char **argv) {
     }
     argc -= optind;
     argv += optind;
-    
+        
     gInFile = stdin;
     gOutFile = stdout;
     bool iremove = false;    

pixz.h

@@ -104,6 +104,7 @@ int queue_pop(queue_t *q, void **datap);
 
 #pragma mark PIPELINE
 
+extern size_t gPipelineQSize;
 extern size_t gPipelineProcessMax;
 extern queue_t *gPipelineStartQ, *gPipelineSplitQ, *gPipelineMergeQ;