diff --git a/lib/compress/zstd_compress.c b/lib/compress/zstd_compress.c
index 6f369eba..7fccc180 100644
--- a/lib/compress/zstd_compress.c
+++ b/lib/compress/zstd_compress.c
@@ -2756,6 +2756,7 @@ size_t ZSTD_compress_generic (ZSTD_CCtx* cctx,
                               ZSTD_inBuffer* input,
                               ZSTD_EndDirective endOp)
 {
+    DEBUGLOG(5, "ZSTD_compress_generic");
     /* check conditions */
     if (output->pos > output->size) return ERROR(GENERIC);
     if (input->pos  > input->size)  return ERROR(GENERIC);
@@ -2798,7 +2799,7 @@ size_t ZSTD_compress_generic (ZSTD_CCtx* cctx,
 #ifdef ZSTD_MULTITHREAD
     if (cctx->appliedParams.nbThreads > 1) {
         size_t const flushMin = ZSTDMT_compressStream_generic(cctx->mtctx, output, input, endOp);
-        DEBUGLOG(5, "ZSTDMT_compressStream_generic : %u", (U32)flushMin);
+        DEBUGLOG(5, "ZSTDMT_compressStream_generic result : %u", (U32)flushMin);
         if ( ZSTD_isError(flushMin)
           || (endOp == ZSTD_e_end && flushMin == 0) ) { /* compression completed */
             ZSTD_startNewCompression(cctx);
diff --git a/programs/fileio.c b/programs/fileio.c
index 6dc43de8..1319a575 100644
--- a/programs/fileio.c
+++ b/programs/fileio.c
@@ -446,6 +446,7 @@ static cRess_t FIO_createCResources(const char* dictFileName, int cLevel,
             CHECK( ZSTD_CCtx_setParameter(ress.cctx, ZSTD_p_targetLength, comprParams->targetLength) );
             CHECK( ZSTD_CCtx_setParameter(ress.cctx, ZSTD_p_compressionStrategy, (U32)comprParams->strategy) );
             /* multi-threading */
+            DISPLAYLEVEL(5,"set nb threads = %u \n", g_nbThreads);
             CHECK( ZSTD_CCtx_setParameter(ress.cctx, ZSTD_p_nbThreads, g_nbThreads) );
             /* dictionary */
             CHECK( ZSTD_CCtx_loadDictionary(ress.cctx, dictBuffer, dictBuffSize) );
@@ -797,7 +798,8 @@ static int FIO_compressFilename_internal(cRess_t ress,
 
     /* init */
 #ifdef ZSTD_NEWAPI
-    CHECK( ZSTD_resetCStream(ress.cctx, fileSize) );  /* to pass fileSize */
+    if (fileSize!=0)  /* if stdin, fileSize==0, but is effectively unknown */
+        ZSTD_CCtx_setPledgedSrcSize(ress.cctx, fileSize);
 #elif defined(ZSTD_MULTITHREAD)
     CHECK( ZSTDMT_resetCStream(ress.cctx, fileSize) );
 #else